Deceased account harrassment

My father passed away in July 2021. MBD has been calling me 4 or 5 times a day even though I have emailed all the information they initially requested (certified death certificate, Notice of Death and Certified I.D. to ***. I'm still getting these harassment calls Today it is only 9:20 and I have already been called twice. Once with a robocall. Whenever an actual person calls, I ask to speak to a manager and the call immediately gets ended. I'm at my whit's end.