Cell C Jeopardise my Credit Record

Cell C Jeopardise my Credit Record through *********** agents.

I updated my bank account number with Cell C earlier this year, Agent decided to only update for one account that I have with Cell C only. Now my previous bank has been Charging me returned debit order of R150, each month. This has ruined my credit record. Cell C just called me reminding me to pay. I have logged the change request more than 3 times..... My number : **********