Capitec *****s

I have been banking with capitec for a very long time I had a loan with them and paid it up two months later they contact me via text there is an outstanding amount apparently you have to pay interest for.months you did not have the loan my question was why was interest not added in that balance. I have changed banks because of all the bank charges you get charged to swipe charged for sms charged for just about too much things they are ***** they called me I explained my situation and there was no other balance when I made the payment why that would be misleading they added the extra after I paid the balance now im being harrased everyday for a R425 I've asked for my complaint to be logged nothing there customer service agents thinks they can handle and treat you exactly how they want to there should be a law against banks who do this type of thing I will never recommend capita to anyone ever again now my credit file is harmed we already live in a country where prices go up your salary stays the same . How can u go about taking them further im not done with them .