Billing Discrepancies

Last year around August i have renewed/upgraded my contract which was towards expiring. all went well, later on my debit date was changed without my consent. i only knew about this when they debited my account on a wrong date and on top of that i was penalised for the bounced debit. all this happened while my account is up to date not owing anything to Telkom. when i query this i was told to refer to the Ts and Cs. without them acknowledging the changes that took place. the call centre agents are so terrible, can't assist at all no empathy shown at all. i was told to make a full payment and they will credit my account. after doing just that nothing happens. Telkom's packages are structured well and affordable however, their service is appalling, mostly billing.