Incorrect settlement Figure

good day, I called the RCS call center on date 27/07 to get all my account settlement amounts for Game, Makro, Super quick was put on hold by the call center lady then she came back to me and gave me the settlement figures for that day and also provided me with the bank accounts where to pay via EFT, paid the amounts as I had received a lump sum of money to close my accounts. Called again on date 04/08 to close my accounts to my surprise my Game account was still outstanding with R 560, apparently the lady that help me forgot to include it on the figure as it was pending on their side. Advised the team leader Shaun that I wont have any money going forward cause of the lump sum I got to pay my account and closed them, my salary will be paying off the lump sum, he said sorry but I need to pay it despite the error they did on their side. I am furious and unhappy at the moment don't know where I'll get this money, please get someone to look into my case or let me know if I should escalate it to the ombudsman going forward.