Paying account of R450 for 2 years

Good day,<br> <br> In the summer of 2013, I used my RCS card at Checkers in Swellendam for the first time and spent around R450. Ever since, I have paid monthly but the account stayed at the same balance the whole time. I always paid the installment or more, never less. At the end of May 2015, the balance of this account was still R459.87. I paid this full amount and asked for the account to be closed. I was then told to pay an extra R3.70 to have the account closed. <br> How is it possible that after 2 years of paying this account monthly, I ended up paying more than three times the original amount? I would like an explanation and a statement that clearly shows my payments (I have all my receipts), the interest and balance. <br> I expect your soonest response.<br> Regards,<br> Liesl