account payment

Hi Sir/Madam<br> <br> I made a payment of 299 via EFT for my credit card, before the due date,now RCS is claiming that I owe them more and have blocked the card,i sent them proof of payment,wasted lot of time but only to be treated like a ******** by <br> the rude call center staff,i have tried everything and I don't want to be a bad debtor.the staff is always insulting and rude and always lying to me saying my problem is solved,but when I check again the debt collection is in my case,,,,please help,,,desperate