WRONG amount debited since last year July 2021!!! WITHOUT COMMUNICATION and no response when queries are logged!!!!!

My debit order on my contract is R320. They have been debiting the wrong amount since last year July 2021. Been struggling for 3 months to get my re-fund where they are telling me it shows on their side I am being debited for R320, I have sent my bank statements showing the wrong debiting going on. Froze my account because I wasn't in the area to gym for 3 months - emailed me that the request has been actioned and today they debit AGAIN more money off my account than I have signed for on my contract. This is *******!!!! How can you take more money off a clients account than what he/she signed for??? Been trying since last year July to sort this issue out and the same story each time. Then they tell me the account is frozen but the full amount still goes off my account??? Been trying to sort out the issue for the wrong money taken off my account than what I have signed for, bit NOTHING comes to a point. Please can someone assist me what to do. Because I am at the point that I want to sue because of this. This is *******!!!!