Barclaycard visa in association with Littlewoods! who's telling the truth?

Hi

Im looking for some help and advice in regards to a credit card a relative of mine took out from Littlewoods which was financed by Barclaycard. The account went into default years ago after the relative's income was reduced due to a cut in her employment hours at work. Since then the debt has been passed through to several debt collection agencys and is currently with Cabot financial. Through them a payment plan is set up, although there has been continual interest added to the debt which is now increased to more than twice the original value.

Recently i had tried to reduce the debt for this relative by using a no win no fee agency that can claim back credit card charges and interest charges. They won for her nearly £500 back. However when we were trying to process the claim for her the no win no fee agency sent a letter back saying we had said an incorrect reference number. This number had been taken directly from a Cabot statement as we expected it to be correct for the debt she was paying. But we were told it was wrong, so the relative dug out an old copy of a credit card statement and took the credit card number from there. Cabot had been quoting a 13 digit reference number not the 16 digit credit card number. I know most debt collection agencys use the actual credit card reference number usually as well as there own reference number.

So is this legal for Cabot to be claiming repayments for an incorrect reference number? Also the relative had payment protection on this credit card and we are as yet to find a bill for it but we suspect the reference number they are using is the payment protection reference number.

Although Barclaycard wrote to the no win fee agency to say that they would 'credit the account with the money for charges, Cabot has yet to contact the relative to notify her that the balance has been reduced. Instead they sent a letter which made me laugh, saying that they had received recent confirmation that she lived at this address and that the debt was in arrears and she needed to phone them. This is in spite of the fact that she has been on a repayment plan for 2 years which she has been paying on time. when phoned on friday on my relatives behalf they would not speak to me, when asked to speak to the relative i told them the saturday around 12pm would be a good time to call and they said they would phone back. But the did not call us back.

Can we dispute this account? Is it legal to be paying for a debt under an incorrect reference number? Surely if we tried doing that it would be fraudulent? Barclaycard have already accepted they were in the wrong for the credit card charges can we get this debt written off? My relative is nearly 60 has other debts there is no way she will have them paid off before she goes on her pension as she is in a low paying job, has no qualifications and she spent the best part of 20 years bringing up children and not working. The stress of it all over the past 5 years have lead to chronic depression with several months off on the sick.

Please if anyone could offer some help or advice it would be greatly appreciated.