Absa bad service

Im very unhappy today absa deducted R100 from my account for unauth dr bal i called then and spoke to a rude lady saying my account was in a minus and then they take R100 so i asked her when cause its a new account and she give me a date last month i swip for 29 rand or so i told her but that time there was money in the account and she said yes but it when off only about a week later when there was no money in my account so i told her then its not my fault cause the time i swipe there was funds availible so its not my fault and she say it is and 100 will be deducted every time this happen i feel its not my fault they phoned me back and i told them im gonna leave a complaint and she say thank u and dropped the phone in my ear