RCS placing my account in arrears for no reason

I opened a game account late last year. my first payment was due on the 1st of January 2016. I collected their banking details from Game in order to do a internet transfer. I paid my account via EFT on the 28 Dec2015 and quoted my account nr as reverence. No I receive a mail stating that my account has been placed in arrears reason being that according to them I didn't make a payment on my account.