Debit order not honoured by Capitec

The bank was supposed to debit an instalment on the 15th but failed then on the 16th a debit happened and returned short a couple of hours later. On the 17th I got a call from Capitec and I was asked why payment wasn’t made and I explained and no solution or proper explanation was given. Today I am told that it is my fault and an authorisation was not received by the bank from me. I was told that I did respond to a debicheck which happens every 3to 6 months. My issue is that there is no explanation about the money that got returned and for what reason and being told that my profile will have “dent” for arrears and non payment because of the bank’s failure to debit for 2 days . I am so upset with this bank as this is now happening for the 2nd time this year and I’m given some nonsense explanation that just doesn’t even make sense. I wish I could get funds elsewhere and pay off this loan and NEVER AGAIN USE THIS BANK and I’m going to close the savings account I have currently 😤