I recently purchased an iPhone 11 Pro from 02. The problems I suffered were severe coverage issues. I work all over south and south west London and I could never use the phone to it’s full potential but I tried the phone with an EE sim and it was fine! But with 02 apps would work extremely slowly, I would loose 4G connection routinely and during calls the quality was awful, So I contacted 02 via their online chat and they recommended I’d get a replacement SIM card so I did but yet the issues were still present. So again I contacted 02 via their online chat. They recommended I send the phone off for repair and spare phone would be available but I would’ve needed to pay a deposit for a basic phone, but I said the phone is fine with an EE sim, But they wouldn’t budge from the script. They would only offer a repair, if that didn’t work then it would be a replacement, albeit a refurbished one. So after 3 hours trying to talk to someone sensible I gave up and next day I phoned 02 Instead and managed to speak to someone who was more better at their job, then without fuss offered me a replacement handset which was brand new and I accepted. I gave the new phone a week but yet the problems still persisted, I was gutted so I phoned back and they did not argue at all in this case, they offered to take the phone back and gave me two options, let me take a new phone from a different manufacturer or cancel my line which I opted for. I was about 7 weeks into the contract. The biggest mistake I made was contacting o2 via online chat, They were extremely unhelpful and would not help at all, at one point the chat agent said “ we’re going around in circles” If you are a customer of 02, phone instead the call centre agents are far more understanding and helpful and it seems they more authority in what they can do.