Unauthorised Access To My Account

I had a personal loan with Absa which was settled with their EDC RL DALY, that they use,I even received a paid up letter. This payment once done about a month back so I thought everything is sorted I don't owe any amount. At the end of the month on a Saturday Absa decides to debit my account for my entire salary leaving me with virtually nothing(R14200) when I called the callcentre they advised me that there is nothing they can do I have to wait for Monday. How does one explain to your two small kids that mommy does have any money to buy them any groceries and school things that they require for the Monday. My kids and I had to leave our shopping trolley due to this and God knows when will this get resolved Who gives Absa the right to debit my account for this amount of money,I have not signed any contract for this amount.I was so embarrassed and hurt that I could not furfill my promise to my kids. We're under the CPA act does it state that a bank can debit 95% of ones salary for a loan that was paid up. It's amazing that banks think that they can do what they like and they will be no consequences or they will just say sorry system error,what about the impact to me and my family