System error on RCP

I took out an RCP facility with your institution. In February 2016 I made a lumpsum payment into the RCP and requested that the bank recalculate monthly repayments based on the new balance. The bank has since been debiting my cheque account with the amount stipulated in the revised contract, howerver the facility is not paying down despite me not withdrawing funds. I did my own calculations and realised that the bank made a huge error in their recalculation of the repayment amount. Based on the bank's recalculation I would have to repay over a period of 31 years with interest at over 1000%! I have been to the branch numerous times, logged queries for a recalculation, only to be informed that there is no record of my contract on the system. I have stopped making payments and my account has now been handed over to attorneys. Can someone senior within personal lending please contact me so we can resolve this matter, as I have been sent from pillar to post by your branches and call centre over the last five months?