RCS wrongfully handed me over to debt collectors despite paying and informing consultants of payments.

I have an account with RCS which I paid and brought up to date on 20 March 2020 at Game Stores in King William's Town and now to my surprise RCS has handed me over in May 2020 to debt collectors after having brought my account up to date in March 2020. I have been receiving calls from RCS and I have been explaining everytime to them that I have paid and even have my proof of payment which I even sent to one consultant who called. After that I was a bit reluctant to pay my installment again since my money seems to have gone missing after paying but never the less end April I went to Game again to pay my currents RCS installment and was told at Game that they have never seen the RCS desk staff since the start of the lockdown which was 27 March 2020. So then I could was reluctant to pay to the cashiers again without speaking to RCS staff fearing my money would dissappear again. The amount I paid on 20 March was an amount up to 01 April according to the statement I received from them. Please help as my credit record and reputation is being dented by incompetency from RCS. Please help me