Poor service - ridiculous

I have existing funeral that i have been paying for over 2 years. Since December 2023 I have changed bank details due to other grievance with them. I called them bank January 20 to notify them of the change of bank details and loaded new details. Since January my premiums have not been paid and my policy cover keeps reducing and every month I call to query why they aren't debiting and Im told the same thing , a consultant will call me. They don't I call and log new details and still no action is taken. Im fed up with this bank and have no idea how to sort this out as I have now missed almost 6 premiums due to incompetence. I have the funds in my account right now yet I keep getting messages that premium is not being debited.