Medi Assist — reimbursement issue

Address: 313001

My mother admitted in the listed hospital of mediassist insurance provider.
She was admitted for 4 days and i have provided all the required document.
However they are still again and again asking from some more documents which not sure why required.

She is already passed away and we are already too much disturbed.

We do insurance so that they can help us in our tough time not to increase our troubles declining our claim mentioning a list of documents not provided.