Our medicare costs went up for 2018 by over $300 a month for both of us. Total of over $600. We sold a home we bought in the 60s and had for a rental after we moved out. We are not wealthy people. We have been frugal all of our lives and not got in "over our heads." The things listed in the possibility of an appeal do not fit for us. Should we try an appeal anyway?
Having said that, I would review the tax filing for year 2016 --- is that the year you sold the property? Did you count the house sale as income? Perhaps that is the question or perhaps you had another extraordinary income item.