Should bank pay back old condo fees when unit is re-possessed?

In my association in Iowa, there has been one unit in foreclosure for two years. Apparently it was purchased, but the deal fell through, and the property went back to the bank or lending institution. No dues have been collected in all of this time. Since the "bank" owns the property, shouldn't they be obligated to pay the monthly dues, or does the association need to hire an attorney to make this happen?