I had an o2 contract via a third party (Mobile Phones Direct). My contract ran it's course in October 2024, and I upgraded to a new handset and contract. I wasn't happy with the phone so returned it within the 14 day cooling off period. MPD emailed confirmation that the return was complete and the new contract was cancelled. I logged into my o2 account a little while after and the contract was still showing as active. I called to query it and they assured me that I was out of contract, and free to leave whenever I wanted to, and also sent me a PAC code. I then didn't do anything until a couple of weeks ago when I requested a new PAC code and moved to a SIM only contract with another provider. I have now received a final bll from o2 for £410. I called to query this and after a protracted conversation they say that MPD have charged this amount and they have paid it on my behalf and are now recouping that, and that I should query it with MPD. MPD told me that this was incorrect/untrue and it is o2 charging me. MPD say that they will 'try' to ask o2 to waive the fee. Having dealt with both of these companies I don't feel confident it will be sorted. Nobody is able to tell me what I am even being charged for. They surely can't charge me early termination of a contract that I haven't taken out or agreed to? I have cancelled my direct debit to try and prevent them from taking this amount, but I know this isn't a permanent resolution as I'm sure they won't simply let it drop. Does anyone have suggestions of what I should do next if they don't resolve it? Thanks.