ABSA TAKEING MONEY WITHOUT PERMISSION

on 2020/01/10 I paid my absa credit card R3000. the afternoon they called me and said that I paid R812 short, I mad a arrangement to pay it on the end of January. to my surprise today I seen that they decucted the money out of my savings account. the money in my saving account was all that I had left for the month. Who gave them the right to take money out of my savings account. I want answers , I have been a customer with absa for more than 23 years. I want my money back into my account. Absa you are make transaction that I did not agree on, I am going to close my savings, credit card, and cheq account by you.