BEYOND FRUSTRATED!!

I phoned RCS for a settlement amount on my Makro account. Got the amount, paid immediately, settled the account. The following month they send me a bill again with a R500 balance on it, AFTER I settled the account. I phoned them and asked about it and they then told me that the settlement amount was incorrect that they gave me! Unacceptable! I lodged a complaint about this. They said they will request for the balance to be written off because it was their mistake. 3 Months later I STILL did not resolve this. Every second day I am receiving sms's to pay my account. When they phone me for payment the whole complaint process starts all over again and promises are ONCE again being made that they will get back to me! This gives ME a bad credit record!