The O2 phone number is 0344 809 0202, and you can use this for an O2 cancel contract request, to ask questions about O2 network coverage, or to make any other kind of query relating to your phone and account.
Use your online account area too, speak to the team on live chat, or go into an O2 shop for help.
You can make an O2 online top up onto your account via the website, by calling 4444 from your phone or by setting up an auto top-up.
You can buy O2 contracts online too.
Look out for O2 promo codes that save you more!
The O2 network coverage can be checked online at any time to see what O2's regular and current coverage is in your area.
Buy an O2 sim only for an existing contract online or in the O2 shop, and find out more about O2 wifi calling in the product demo area.