Game store/Rcs account discrepancy

Game stores/Rcs….I write this review with great dissatisfaction,I opened a game store card begging of last year and i was paying consecutively every month until last year October when they told me I have missed payment for 3months.i sent them proof of payments because I was paying via bank approved beneficiary (game stores) on the Nedbank app.they told me it’s not their account and I even when to the Nedbank branch to verify the account,the consultant told me it’s their account since they are the one that confirmed it on their app.up until today my matter was not resolved and my owing balance was going down slowly.last month end I paid via the link they had sent me the previous month to pay with and I emailed the proof of payment but they are saying they didn’t receive the money.this is really worrying me and it’s putting impact on my credit score because it shows missed payment