Having been transferred from Virgin I experienced several days without a signal due to alleged problems with a local mast. No apologies so I closed the account and received confirmation that nothing was due to o2. Weeks later I was advised that I owed another month's payment and was due to pay late costs , my credit rating was also at risk. Their virtual assistant was useless, they do not have an email address to help and their customer service line was unanswered despite very long waits. Following their published advice I visited an o2 shop, their customer agent curtly advised me that as my account had been closed they couldn't (wouldn't) help and I should ring the customer help line again. Eventually I reached a human on the helpline who advised that I was actually in credit but the requested confirmation of this failed to arrive. This is telecommunications company that doesn't want to communicate. Avoid if possible.