Bad service and incorrect billing

So frustrated with Telkom billing department this morning I received a debit order of R1911.96. What upsets me is last month when I phoned their billing department I was told that there has been a system error and will be fixed.l for the last 3 months my account was debited even during this lockdown for the full amount now my account shows I’m in arrears which is supposed to be up to date y is telkom making their problem mine if they have system errors that has got nothing to do with me please fix this ASAP because this is bad service and I have my bank statements to proof all payments has been made