Prolonged delay in paying out deceased estate.

I am the executor of a deceased estate. The deceased had investments with Nedbank, Allan Gray and Vunani. Allan Gray and Vunani resolved and paid out within a days of verification. Nedbank keeps stalling and has still not paid out the deceased accounts after confirming on 29 October that verification had been completed. This was Nedbank response on 23 November 2023:

"Reference Number ***1 is logged for pay-out. We are unfortunately unable to provide a turnaround time due to high volumes."

A bank busy to pay out money? Its now 16 days later, and we are still in the queue waiting for payment. Why would anybody still bank with Nedbank?