Shocking service from Bidvest regarding Mandate

What is going on with this bank??? I am also one of those that signed the Mandate for 2025 and it came back with an Unsuccessful error. It does not allow you to resubmit although I know the details are correct, this is the 4th year of doing this mandate. No body answers the many emails I have sent and no one answers any phone numbers I have called. I am now out of pocket by many thousands due to me from Airbnb. How on earth is a person supposed to fix this problem so that payments can be received as usual????????? Shocking terrible service from this Bank, Avoid them at all costs.