I have cancelled the direct debit. It is T-mobile who then pester me for the money and it was not them who set up the direct debit it was Mobiles.co.uk

Hi Everyone, this is my first post... I'm lookng for some advice about a worrying thing that has recently happened tome! I purchased a new mobile phone with contract from Mobiles.co.uk which is part of The Carphone Warehouse. They requested my bank details to check my identity which I gave to them and they debited 1p from my bank account. Received my new phone and all was going well until I received a text from T-mobile saying that my direct debit was returned unpaid. I immediately checked my online banking which had sufficient funds to pay them the line rental but I realised that there was not even a direct debit set up on the account from T-mobile. I checked my other bank accounts and found that they (carphone warehouse) have set up a direct debit on a very old bank account that I no longer use. This means that they have saved these bank details on their system for many years from when I last had a contract with them (over 3 years ago) and set up a direct debit without my permission then tryed to take money from a bank account that I no longer use therefore incurring me a £35 bank charge! I have tryed to contact Mobiles.co.uk on 5 occasons now and spent approximately 90 minutes on hold - I have not been able to speak to anyone from the compny to discuss this matter. I have e-mailed their customer services and requested that a manager contacts me regarding this complaint (this was last friday and they have not responded) Can anybody advise me as to what my rights are and if they are allowed to do what they did? Please help! Many thanks