Are you just confused about the tax years? A 2017 return would have been prepared and filed in 2018----after tax year 2017 was over. Similarly, a 2018 return would have been prepared and filed in 2019, and so on.
TurboTax saves returns in your online account for seven years, and then they are gone. That is why you should always--always--always---save your returns as a pdf and print copies for your own records.
Not sure what you are saying will cost $900-----but TurboTax is not trying to make you pay $900. It sounds like the state may be saying you owe the state $900 if you made a mistake on your state return.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
