You cannot amend a tax return for 2015 to claim a refund of taxes. You are only allowed to amend a return for three years from the due date of the return to claim a refund.

The TurboTax software for that year is no longer available from TurboTax.

So what do we do to file? 

The filing deadline for the 2015 individual tax return was April 18, 2016. So in order to claim any refund, you needed to file by April 18, 2019. You are past the deadline to receive a refund for tax year 2015 and can no longer file to claim it. Would you have had a balance due for the 2015 tax year?

how do i report my 2015 taxes? or i don't?

@evsword 

2015

Form 1040  https://www.irs.gov/pub/irs-prior/f1040--2015.pdf

Form1040 Instructions  https://www.irs.gov/pub/irs-prior/i1040gi--2015.pdf

Form1040A  https://www.irs.gov/pub/irs-prior/f1040a--2015.pdf

Form 1040A Instructions  https://www.irs.gov/pub/irs-prior/i1040a--2015.pdf

Form 1040EZ   https://www.irs.gov/pub/irs-prior/f1040ez--2015.pdf

Form 1040EZ Instructions  https://www.irs.gov/pub/irs-prior/i1040ez--2015.pdf

https://www.irs.gov/filing/where-to-file-paper-tax-returns-with-or-without-a-payment

.  If you owe taxes, the interest/penalties will be calculated by the IRS based on how much you owe and when they receive your return and payment.

turbotax is not the only tax software 

at least one of the top three vendors will  still sell you the 2015 software program.

We're not allowed to mention them here.