Am I responsible for my deceased mother's usda loan after my brother signed the house over to me? No contact from them for 7 years of me trying.

My mother died Feb 2018. She left her house to my brother but he didn't want it and signed it over to me. I have the original deed to prove that. When we did that I sent in the paper work to take over the USDA loan but that was the time when the government shut down. My paperwork was never processed through. It stopped at a customer service. I have tried calling for the past 7 years to try and find out what I need to do to get the ball rolling to no avail. No one would call me back nor would they answer. I even went to the office in Jefferson on a week/work day and not a soul was there. I've gotten no phone calls, no bills, no nothing from them. Until about a month ago. I got, well my mother got a foreclosure letter and the past due amount is for 7 years. I'm self employed. I take home repair jobs as they come. No taxes have been filed for a couple of years because of this. My name is on the deed for the past 7 years. Squatters rights. Do I have to apply for the loan assumption?