All resolved now. Thank you
Surely you must be getting through to be told the bank details are wrong?
I suspect they have written a number down incorrectly. In these circumstances the payment can’t go through. When you speak to them next time and get the same story, write down the date, time, and the name of the person you speak to, then insist on speaking to the supervisor. If that doesn’t work contact your MP.
Are you your sister’s DWP appointee?