I switched my account to other network provider after 18 Years from being with o2. Because I received very bad customer service and signal coverage. Now after 4 month switching the account and 4-5 times calling them to close my account (my contract with them already was ended), still they send me monthly bill and charge me extra for late payment!!! I paid about £100 extra for the sim card I Dont have and the service I don't use. every time I call them takes me about an hour on the phone and they promise to send me final bill and closing the account but again next month they send me a new bill !!! this kind of scam has to be stop by UK government