RCS is robbing me!

I have a Dion Wired store card through RCS and I make monthly payments, on my June statement a payment that I made in May of R300 reflects and one I made in June of R400 reflects BUT the May payment I made of R300 reflects as reversed, I called to query this and I got told it was an error on their side and they will fix it, THEY DIDN'T so I called again a couple of months later and they told me not to worry my account was not in arrears so it's okay and it should be adjusted, THEY DIDN'T. I called again and they escalated my situation to the payments department and then I received an SMS that says my account will be adjusted so I waited for my statement to see the adjustment and of course THEY DIDN'T ADJUST IT! They claim that it has been adjusted on their side but the problem is it doesn't reflect on my side, the June statement has an opening balance of R1970 and a closing balance of R1664, how is possible that I pay R700 and that is the difference, the last person I spoke to calculated every single statement from May 2019 to February 2020 and she also could not see where the R300 was allocated! I only have R322 left to pay and I refuse to pay it until they adjust my account! The service is so bad its unreal, AND they have the audacity to send me smses typed in CAPS telling me to pay for my account!