any help re: sainsbury's bank

honory

Hi, I have a little problem with Sainsbury's bank and need a little advice! (sorry it's so long!!)
After my husband was made redundant we sought help from the CCCs to cope with our awful debts. They managed to get everyone to freeze the interest and we have been steadily paying off everyone over the last 2 years managing to clear 3 and have three left. The only creditor who never agreed to freeze the interest was sainsbury's and we just accepted that state of affairs - paying off £77 and being charged £130 in interest every month.
Recently I contacted the CCS to arrange an increase in my payments and mentioned that sainsbury's was crippling our debt repayment plan. They had written to them on numerous accasions and received nothing back. I took it upon myself to ring them to see whether they would agree to freeze the interest when they spoke to me directly. After much confusion - the CCS had presumed that my account had beeen passed to Blair Oliver Scott the debt collection agency but it hadn't I was still in the retail collections department within sainsbury's bank - they at first agreed to freeze the interest after the cccs had sent an uptodate financial statement to them (they hadn't received one since 2004) .
CCCS were eventually able to do this but in between many calls it eventually transpired that my account had been overlooked for 2 years. The interest had been charged but no 6 month interest free period had been allowed. Suffice to say that the bank agreed to refund 6 months worth of charges but they decided to cancel their previous decision to freeze interest and I am now back to paying it and also the overlimit fees and charges that they want to apply. Is there anything I can do?? Has anyone a similar experience with sainsbury's bank? They just seem really out of kilter with my other creditors in their decision to not freeze interest. Any advice is much appreciated!