ABSA personal load terrible service

I have been trying endlessly since February to update my banking details on my personal loans debit order. No matter how many people I speak to or send mails to, no one updates and collects the debits. ABSA then has the audacity to threatening black listing me. I have tried everything and yet nothing. They phone, and drop the call once I answer. When I speak to someone, they say they will escalate and resolve but they don't. ABSA your service is absolutely pathetic!! How do I get this resolved???