Apple Card Support through Goldman Sachs

Is there any way to contact Support for the Apple Card beside the 877-225-5923 number? This number has been busy for 4 days.

My sister died and her Apple Card account is past due. I was able to get through on the number on December 3rd and spoke with a supervisor who said they would have to have someone call me back about closing the account and paying the balance. No call back in two weeks. I've tried calling multiple times each day at varying times, but the number always just rings busy.