Banking details not changed

I recently changed banks and with that came me emailing all of my creditors etc to update my banking details, I then received a call I believe it was on the 11th August 2023, and I asked the call centre agent that called if both my policies were updated, she confirmed yes,comes month end only one debit order goes off and yesterday I sent another email to query why the details weren’t updated and sent my banking details again, instead of updating Hollard sends me a message to say I am currently not covered…I mean how difficult is it to update banking details???