Disputed rejection fee

I informed Telkom of my change of banking details via email, and they decided to debit from the bank that I don't use anymore. Red flag 1 I even went to the branch to update the new banking details. (Negligence and poor customer service). Now they want me to pay the rejection fee of the same amount R202.70 despite the fact that they had to debit the updated bank and was successful. I want the rejection fee to be waivered.