I filed my 2015 taxes using turbo tax, do you have it on file?

Access to prior year returns:

https://ttlc.intuit.com/questions/3355524

How do I get a copy of a return I filed using online TurboTax?

https://ttlc.intuit.com/questions/1900748

How do I get a copy of a return I prepared using desktop TurboTax?

https://ttlc.intuit.com/questions/1900639

You can also get a free transcript from the IRS:   

https://www.irs.gov/individuals/get-transcript

How to upgrade to PLUS

https://ttlc.intuit.com/questions/3404582-how-do-i-upgrade-to-plus-if-i-already-filed-my-2016-tax-return

https://ttlc.intuit.com/questions/3796106-why-do-i-have-to-pay-to-access-my-prior-year-return