RSC refusing to close my jet account.

I've been trying to close my account with them for the past 2/3 months after paying settlement account with no luck. It keeps accumulating interest(its currently on R650) and affecting my credit record. I'm desperately asking for help regarding this because I asked for the account to be closed long time ago several times, obviously RSC agent dis not do his job. Yesterday I went to the store and requested to speak to one of the managers at RSC call center, he told me he doesn't have time to listen to me and he was very rude and arrogant, forgetting that I spent 2 hours on the phone trying to get help regarding this matter. Where can I get help regarding this?? My credit score is badly affected.