Account not debited

I have a contract with Telkom, my experience with their billing system is that my account has not being debited for the past 6 months, I have been making either manual payments or eft and at some point I even had my account being suspended for none payment, this none payment is not by my own doing because I always ensure that my account has enough money even after making the manual payment, I have been charged a rejection fee amount for "none payment". I have sent banking statements in attestation that my account was never debited, why then the rejection fee? I am told that their billing department will attend to the matter within their SLA which is 72 business hours and that someone from that department will call and explain the reasons why, to date I have never received a call and this problem is still going on, and when I call to enquire I got assisted by some other consultant who was rude, told me that I should go and check with my bank, the audit trail of the debit order will never show on the bank statement, I was shocked because how then informs the fact that my account had insufficient funds if I can not prove via my bank statement. I hope this will expedite the process because Telkom has shown me that my matter has not being prioritized for the past 6 months.