Admin Department constantly busy

On Friday the 4th I received a text advising I was late on a payment on my RCS game card, I settled and closed 4 months earlier. When I called the call centre they had advised that I only paid the next day and my account had then added interest. Immediately arguing with this agent I advised that I made the payment almost immediately on the same day. BUT Agents always know better than you, with there scripted lines. I sent proof confirming my payment to their admin department. Was told 24 - 48 business hours was the turnaround. After 3 previous calls today, the 9th I escalated and spoke to Keenan (Team Leader) Nothing had been done on my account, not even the reversal of the incorrect amount still linked AFTER I sent through proof of payment. The admin department, had NO managers available, the AGENTS REFUSED to take a call from the client. My email was not even looked at or responded to. RCS your staff is putrid and all of them especially your admin division require customer service training! Get to understand your institution and realise that your mistakes impact the lives of the public. Your non existent attitude to actually assist speaks volumes of your organisation. PATHETIC