I’d been a loyal customer to O2 for years. I recently found out that I was being charged nearly an additional £40 a month for a number/device that wasn’t mine. Thought it was an additional charge for insurance or whatever, but it turned out it was not. My partner and I did the math and I’ve paid nearly a grand towards this company in that time. Their idea of compensation wasn’t even a quarter of the amount I’ve paid them over the two year period. Terrible customer service, in the process of terminating my contract with them now. Would not recommend unless you want to be scammed almost a grand!