An act of desperation! Please Help!

I am only resorting to this public complaints platform because Old Mutual flatly ignores any email communication. My parents passed away in 2020 and 2021, and Old Mutual is the nominated Executor of their estates. I have been in contact with Old Mutual since October 2020, provided all the requested documents - and there is still no resolution. Meanwhile the banks keep charging banking fees on their accounts because they are insisting on a letter of Executorship before closing the accounts - which Old Mutual has simply failed to provide. Please Help!