Nedbank cannot trace payments to UIF

In 2002 I set up a Beneficiary on my Wife's Nedbank account for UIF. I paid every month for 20 years escalating the amount. The monthly payments appear on the bank statement as debit UIF. I have a problem with UIF. So I asked Nedbank where the money went to. They cannot tell me. So I cannot prove to UIF I have paid on behalf of my domestic worker for her to receive her benefits. WHY?