Unpaid Claims

My mother in law passed away in November 2017. There are outstanding medical bills from the hospital I have been trying to finalize since the start of this year. I have made numerous calls to the center as well as emails to the claims department, but to date no one has been able to confim why there is an outstanding balance on the hospital account. As the agents who helped me were unable to determine which amounts were not paid I was constantly told to contact the hospital again and get back to them with the exact amounts and dates. I don’t understand why Bonitas cannot contact the hospital accounts department directly to confirm which items have not been paid, it makes not sense for me to be the middle man. Yet after this I have still not received any confirmation to why the account was not settled in full. For us to conclude the estate we need to finalize this issue. If there is a legitimate reason for why these claims were not covered one would think such reason could atleast be coveyed to us?