DISGUSTING ABSA SERVICE

I have an absa account that have made arrangement to settle with Vericred as it has been handed over to them. I'm currently paying R300 every month. On the 24th July an amount of R1851 was debited from my account without my knowledge and when I called absa collections their telling me it's a debit they made as I haven been making payments but I spoke to vericred on the 25 July and they dont even pick up that amount and did not authorize for that. If my account is handed over who gives absa right to just debit without checking with the people the account is handed to if there is anything happening with the account. So my concern is these people are not in communication and people are just debiting however they want in my account. I need my R1851 reversed because there is an arrangement already done to pay off this account I don't expect unknown debits as they have inconvenienced me drastically. RIGHT NOW IM VERY ****ED OFF WITH THE SERVICE IM GETTING CAUSE EVERYONE IS SENDING ME FROM PILLAR TO POST. I WANT MY MONEY BACK ASAP. Please can this be sorted out before I take it further.