account not updated

on the 1st of December I paid my due monthly installment. After seeing that my account was not updated, I phoned to make sure that you guys received payment and I also sent you a proof of payment. The consultant informed me that you had a problem with your EFT payment allocation systems and that the system would be updated accordingly. I just checked and it still says that I'm a month behind (which i'm not) and thus it reflects that I must make a double payment this month. Also I would like a breakdown of fees/ interests applicable as I'm unsure of the amount credited back to my account after payment. Please update your system. This issue refelcts badly on my credit report as a month missed in payment.