Extremely poor customer service

RCS is administering the Sanlam Moneysaver Credit card. I must say, what a disappointment it is dealing with those consultants. Im trying to resolve interest charges on my account since March 2024. On a monthly basis they keep on charging me interest, while i pay my full balance on the statement. PLEASE, explain the interest charges...i just don't understand why or do i miss something. How is it possible to not be able to resolve queries since March and we at the end of May already. I requested thrice already to cancel my credit card and no one ever get back to me. This is very much disappointing and than they want to add more service charges to my account. I need urgent help from a superior in that business.