No balance on the loan account

I have a savings and loan account with the bank, I paid 75% of the loan account with a lump sum in October. I was advised that the balance is about R18000. In November the debit order was debited and yesterday I called the call centre as the December instalment was not taken yet. I was advised that the instalment was taken from the lump sum amount. PLEASE TELL ME, how many accounts do I have? How possible is it that the instalment can hang somewhere where the consultant had to put me on hold for more than 20 mins and I had to drop the call because I guess he had forgotten about me and knocked off. I AM DISGUSTED AND DISSAPPOINTED WITH YOUR SERVICE. Please advise me of the balance so that I can move my business somewhere else.