Worst service from Standard bank

I paid up a Standard bank account that was in arrears on the 16th June 2018. I paid the settlement amount into same account that I made the monthly prearranged payments in. The attorneys that handled the account cannot found the payment and Standard bank are also struggling to found the payment. I send the proof of payment to the attorneys and Standard Bank with no luck. I just want a paid up letter to get this of my name.