Absa listed beneficiaries STILL not working

Tried to pay Unisa and Sars, both of which are listed beneficiaries at Absa. I keep getting the same error: "013-Enter a valid beneficiary account number". The problem is that the account number is pre-populated by Absa and there is no way I can change it. It also won't allow me to add either beneficiary manually as the beneficiaries are apparently listed beneficiaries. This is really frustrating and, by reading other reviews, this seems to have been a problem for a while which Absa is not sorting out. Please assist!