You're trying to contact someone, but you're not sure if your text messages or voicemails are getting through. It may have crossed your mind that your number has been blocked. You might even know for definite that your number has been blocked if the other person tells you.

There may come a point when you urgently need to contact someone, but you can't because your number is blocked. In these extreme instances, there are several ways that you can continue to contact someone even if your number has been blocked.

It's important to remember that repeatedly contacting someone who doesn't want to be called or messaged is classed as harassment. You could be reported to the police and face legal proceedings.

We've compiled a guide to help you if you think your number was blocked by accident or you legitimately need to contact someone even though they have blocked your number.

Below are some of the methods you may wish you try to contact someone who has blocked your number.

Use another phone

It's only possible to block calls from a telephone number rather than a specific individual. This means that you can still call someone's number if you use a different phone (as long as the other device hasn't been blocked too). You could try using another phone that you own (such as a landline), someone else's phone or a payphone.

Bear in mind that the new device you use can also get blocked. If this is the case, you will no longer be able to contact the phone number through that particular device.

Hide your caller ID

It's possible to hide your caller ID so that their smartphone won't recognise your number. This allows you to bypass the block, although there's no guarantee that the individual will answer your call. Your phone call will be listed as 'unknown caller' or 'hidden caller ID', which may look suspicious to the call recipient, and they choose not to answer.

To hide your caller ID, you will need to go into your smartphone's settings. In the Phone app, you should see a subsection that is called 'Caller ID'. You should be able to tap a toggle button that will hide your caller ID from other phones.

Hide the number using dial code

To mask your phone number from the recipient's phone, you can use a specific dial code before the phone number. In the UK, the code is 141 and in the US the dial code is*67. For example, if the number you are calling is 4155552671, you would need to dial *674155552671 in the US or 141 07415555267 in the UK.

Adding *67 or 141 before their number will make your number appear as 'unknown' to their device, which allows you to bypass their blocking system. However, this technique doesn't work when you call the emergency services (such as 999 or 911).

This method only works on a call-by-call basis. You would need to use the dialling code for each new phone call. Otherwise, the recipient's phone will continue to block your calls.

Change your number

Your phone number, rather than the device itself, is the only thing that can get blocked. This means that you can change your phone number if you want to contact someone who has blocked you. However, this is an extreme option and should only be done in urgent circumstances.

You can change your phone number by contacting your service provider and asking them to give you a new number. Most service providers will ask for you to provide them with a reason for the change request.

Use a random number generator app

You can download an app that generates a random number that can be used when you call someone. The random number will appear on the recipient's phone rather than your real number when you call them. They won't be able to call you back as the random number isn't tied to your phone. They would need to phone your real number if they wanted to phone you.

If someone has blocked your number, it's usually best to refrain from contacting them another way. They could report you to the police on the grounds that you are harassing them if you continue to find other ways to call or message them.

You may feel as if it is necessary to contact the person because you want to apologise for something or if there is an emergency. It's not okay to keep calling someone if you want to abuse them or act in an otherwise unpleasant way verbally. You should expect that the other person may not want to talk to you, no matter your reason for calling.

Under normal circumstances, it's not strictly illegal to call someone when they have blocked your number. However, it's illegal to harass someone through phone calls and texts or call them if they have a restraining order against you. If you call someone and they feel as if you are harassing them, they can report you to their phone company or the police.

Malicious and obscene phone calls are criminal offences. The recipient of calls such as these can report the caller to their phone company and the police whether they know the caller's identity or not.

The recipient may not mind that you have evaded their call-blocking system if you have a valid reason for doing so. However, this isn't a guarantee. It may be a better idea to ask mutual friends to speak with the person on your behalf so that they don't feel threatened or harassed.

There are several ways you can find out whether your number has been blocked or not. One way to test whether you have been blocked is to phone the person's phone. Unblocked numbers should ring between three to 12 times before going to voicemail. However, if you are blocked, you might hear one ring before the call goes straight to voicemail.

Another way to test is through text messages. On text messages sent from an iPhone to another iPhone, the message should be marked as 'delivered' if they were successfully sent through to the recipient's phone. If you don't see the 'delivered' mark, your messages will not have been received by the other person's phone. However, it's worth noting that messages sent to and from an Android phone won't show this feature.

You can use other devices to phone the person's number and see if your call goes through. It may prove that your number has been blocked if the person picks up or the phone rings for a longer period of time before going to voicemail when you use another phone.

How do you block a phone number?

You should be able to block a phone number on your smartphone by going to your device's settings or call history. You will need to identify the number you want to block and select the 'block' option.

The process for blocking a phone number on a landline phone is slightly different. Your service provider should be able to provide information on how to use the call-blocking feature. They may offer you an add-on service that enables you to choose which numbers you want to block. You might also have an option on your device that allows you to block the last number to have called. Bear in mind these options won't work if the call comes from a withheld or unknown number.

How do I unblock a phone number?

You can unblock a number on your smartphone by going to your device's settings or call history, selecting the number that you want to unblock and tapping the 'unblock' option from the drop-down menu. On a landline phone, you should visit your service provider's website or phone them to find out how you can unblock a phone number.

There are a number of ways that you can call someone even if they have blocked your phone number. The simplest option is to call them from another device, such as another person's home phone, a friend's phone or a payphone. You could also add a dialling code in front of their phone number (such as 141 in the UK or *67 in the US) which will hide your number from their phone.

There are apps that can generate a random phone number for your device. The other person's device will see the generated number rather than your real number, which will bypass the call block system. You could also go to your phone's caller Id blocking settings and choose the option to 'hide caller ID'. In extreme circumstances, you could change your phone number by contacting your service provider.