Missing PAYU transaction cause RCS to show their true colors wrt customer satisfaction and relations

I have been using the same payment method on the RCS Phone APP by name of PayU for over a year. In December I made a payment on the 26th which cleared on my bank statement on the 29th. The APP at the time indicated successful (no errors) and as per the transaction on my statement (Bank) the amount due was paid. Much to my dismay, after 01/01/2021 I started receiving reminder messages to indicate that RCS has NOT received my payment. I phoned RCS and they vehemently refused to put me through to finance and advised I contact my bank. I contacted Nedbank who, after 45 minutes on the cell advised they cannot access the info pertaining to this card transaction and cannot supply a reference as it is NOT an EFT but similar to a card purchase. RCS will have to look for an unallocated amount equal to that specific amount and advise on rectifying the miss payment. I have now received message from RCS advising me that the account is now in arrears since payment was not received to date. I have spent between RCS and the bank more than 3hrs on the phone and between the two of them I cannot get an answer. The bank says its paid, RCS says its not... and the sad part is I did my duty and now I am held accountable for this issue and to find a resolve with which NO ONE wants to assist me. The attitude of RCS is just "Its your problem". The bank personnel really tried their best to access the info but to no avail. I am very upset about this and have now raised a dispute with Nedbank to reverse the payment so that I can just simply go to RCS and pay them directly with the money I already paid them and cleared on the 29th. The total disregard for my concerns list RCS as an absolutely "DONT CARE ORGANISATION"