RCS / Makro credit card

I have contacted the call centre on numerous times asking to have my amount owing corrected, I had to ask them to use a calculator to check the numbers themselves after wich they agreed it was overcharged by +/- R10 000, leaving my account in a minus R4500......how is this even possible? I am still waiting for someone to contact me as promised and the account is still not corrected,......very frustrating that there is no proper help in this matter