The data on my 02 mobile phone suddenly become inaccessible so I was unable to send or receive calls or texts or use the data I pay for on my monthly contract. I contacted O2 customer services and was unable to go through the security process to allow them to help me. This is because they appear to have an incorrect email address on file for me. Their only suggestion was that I visit an 02 store with my ID and get it sorted out there. I did this and they could not go through the security questions because there was a problem with the email address! I called customer services from the 02 shop because the shop manager advised us to call them. The result was: neither could do anything to help me! So... I am now left with a monthly 02 contract that I cannot use and I cannot cancel. DO NOT EVEN CONSIDER SIGNING UP WITH 02! THEY ARE TOTALLY USELESS AND HAVE NOT HELPED ME AT ALL! WORST MOBILE PROVIDER EVER!