Paying for something at Amazon won't affect your Online TurboTax account. The only way for a user to unlock returns automatically is to upgrade and pay for a 2016 return in the same online account.
However, you can phone TurboTax Support during the day and explain your situation. Hopefully, they will unlock the returns for you.
By the way, you can still use the product you purchased at Amazon. You can even download the *.tax2015 data file from your online account and transfer it into a new 2016 return that you prepare on your computer.
Following the steps in this article will generate a phone number for you. The number will not appear when they are closed, however. Hours are 5AM-9PM Pacific (8AM-12 Midnight Eastern) 7 days/week.
FAQ: How do I contact TurboTax?
https://ttlc.intuit.com/replies/5566005
