Bad service

I have been a happy client with absa for a long time but now the experience that i received is horrible. I arranged payment relief with them and they agreed that they will deduct 25%of my personal loan but to my surprise they took the whole amount. All my debit order didn't go through because Absa deduct more money and now my account is in arrears of 514.14 because of the unpaid which was caused by Absa. I went to the bank to ask them to write off those unpaid and they said thats not their fault. Absa will you please clear those arrears .