INCORRECT ACCOUNT BALANCE

My Woolworths account was sent to Blake & Associates for collection - the end of August, I was told that my account balance was R5 909.40. On the 5th September I transferred R2 000.00 to Blake & Associated account and the money was not located to my account (my fault). The end of September R500.00 was debited and the end of October R500.00 was debited again, I have been consistent with the payments but the account is not going down. On the 1st November I spoke to Kayleen who promised to escalate the query. Today I called to follow up & I was told the account balance is R5 100.00 and I am being told that Woolworths is adding interest but they cannot explain why - even if the account is in arrears, with the consistent payments, the balance should reduce. Blake & Associates is ripping us off and they do not even send statements when requested by they are quick to send sms's to remind you of the payments. I asked they stop sending me sms or calling me because that only adds to the balance - Woolworths and Blake and Associates must sort my account out.