This time they're threatening us with the debt collectors, omg yay!
We got the letter at the weekend when my parents had come to visit, and my Dad (ex BT) was instantly furious. He does quiet rage and sat there with the letter in his hand shaking visibly along with him.
My partner got on the phone immediately - he didn't want this going on his credit report after all - and was told by the CSR that there are 3 accounts for our property: one phone, one broadband and one for tv. Well that's all well and good, except these 3 are paid by direct debit and we've not missed a payment, so we know that the CSR was talking out of his backside. Not only that, but only one of those bills is addressed correctly - we live in a flat which was converted from the top two floors of a house. We are in "Flat A, [house number]", whilst downstairs is just "ground floor flat" or just plain [house number], so two of our bills are addressed to just plain [house number] and the CSR could not get his head around the fact that that isn't our address. My partner gave up. This extraneous account is also attached to a phone number that not only is not ours, it's not in service at all and we know this because we've repeatedly tried ringing it to check we're not going mad.
We're compiling a list of the account numbers and all blunders from the beginning, and my Dad has offered to write a letter for us to the chairman's office as well as to OfTel. We'll be requesting that all our accounts and address info is corrected, that the extra account is completely killed and that they stop the debt collection taking action (and removing any black marks they've put on my partner's credit report). All this will need to be done within 7 days of the date of the letter (the same amount of time they gave us to pay up, even though it took 7 days for us to get said letter).
I'll update with the letter and with the outcome.