Another Bidvest mandate form disaster

I am yet another victim of Bidvest Bank's utter incompetency. Mandate form filled in eith the same details as always ..payment rejected. Payment made again, to the same FNB account it gets send to every month from the UK ...rejected with reason "incorrect bank account number". Ive had that account since 2006 and know the account number off by heart ...it is not wrong .. Moreover payments have been made for 2+ years with the exact same details to the exact same bank account and lo and behold ...here comes Bidvest on the first payment in Jan 2025 and everything is suddenly broken. How is this possible? Part of this money goes to help someone who has cancer and is unable to work and needs the money urgently.