Complicated POA or not?

California

My grandmother died almost 2 years ago but prior to her death she gave my mother, her caretaker, power of attorney and signed over the deed to her home (which my mom and dad lived in with her and paid the mortgage). The house stayed in my grandmother's name as well as homeowner's insurance. Last month my parents paid my grandmother's mortgage off. My mom has received refund checks from the mortgage company and homeowner's insurance in my grandmother's name but after contacting them, they won't change the refund into her name. She has sent them the POA, deed and death certificate, what else does my mom need to send them in order to claim the refund she and my dad are entitled to?
I am almost 100% sure that my mom is listed as beneficiary on the homeowner's policy and mortgage.
There was no will or trust at the time of my grandmother's death (she didn't have much) and none of my mom's brothers or sisters are fighting for these refunds (approx. $1700).

thanks for your help What is the name of your state?

I am almost 100% sure that my mom is listed as beneficiary on the homeowner's policy and mortgage.

Homeowners' and mortgages do not have beneficiaries.

Your ma needs to probate grandma's estate; the refunds, etc. are assets of the estate.

sorry, I was thinking "life insurance"

thanks for the answer. I just found out my grandmother had a will naming one of her son's as her representative and bequething her house to my mom. Would my uncle, named my grandma's representative, be able to get the checks changed into my mom's name?

Q: Would my uncle, named my grandma's representative, be able to get the checks changed into my mom's name?

A: Yes; he needs to get authority from the probate court.