Payment Rejection Fee

I have a cellphone contract with Telkom Mobile and was recently charged a payment rejection fee of R200.94 I tried resolving this matter by contacting the customer care and was told that a case have been logged with Reference number ********** 2 but when I called to make a follow up I was told that they can't pick up my reference number. I refuse to pay this fee because I made a manual paymet to Telkom days before my debit order date but they still went and debited my account.