I didn't pay any interest or taxes on property for 1 1/2 years?

For the purposes of your tax return, you can only enter the amounts that were paid in 2020.

You need to become current on your interest and property taxes in the future. 

Assuming you are referring to mortgage interest, you can only claim/deduct that in the tax year it was actually paid. The same goes for property taxes, regardless of what tax year you actually paid "for".  Take note that if you also have to pay interest and penalties, then the interest and penalties are not deductible. Besides, due to the COVID stuff, a fair number of taxing authorities are waiving interest and penalties, and a few lenders are doing the same.