Bad Service

I have two loan accounts with Nedbank, in July I received a call from Nedbank offering me a covid relief of which I accepted and I was told I wouldn't be debited and I worked my budget based on that. Comes month end they debited me and when I called I was advised that I shouldn't have been offered the covid relief and they couldn't reverse the debit orders. Now 20th of August Nedbank has debited me twice of which we did not agree on. I know I have arrears on my accounts,, however I did explain that I do not have extra to pay the arrear amount they should only debit 1 installment.