Frustrating customer service and *****!!!

I'm really disappointed on Avis car rental, on the 1st January i woke up with a debit of R350 from them which I don't know what is it for. i don't know of any outstanding amount that I owe Avis. the last time I had a rental with Avis was in August 2020 through my insurance. what bothers me most is that it means because they have my banking details they will just debit money from my account when ever they want. No body even called me to tell me of this money that they debited. They just did as they wish. And when I call customer service I'm not getting assistance at all, so frustrating. Someone help.