Poor service

I had a loan with Royal family cash loans in Roodepoort which was trading as African Brothers before they changed its name.asked for settlement letter on the 15th October 2021 and it was send to me .on the 16th October I went to the branch and paid the amount of R6130 and I was told that the account will be updated on the system and credit bureaus as paid up.until I got the call 3 weeks agofrom the man who claimed to be their attorneys and said I still owe the company the money which I disagree and refused to sign any documents from them about the payment. I called the cash loan and the lady asked for a receipt as proof of payment which I lost and she said the only way to update its for me to show them the receipt.there must be a copy n proof from their side as well and they can use that update credit bureaus n cancel the debt.plrase help me with this issue because it's ruining my credit profile and I will never pay the money that I don't owe anymore.this is the bad service and I'm very angry with these people