Also, how did you pay? Did you pay by credit/debit card as required? For unlocking purposes, you cannot use the option to "pay later out of the Federal refund", even if it is offered. If you did pay by card, did the charge go through? If so, and if you paid in the same account as the prior return, it should have unlocked all prior returns in that account.
So if you paid in the same account, then before phoning Support, make sure it is not a browser issue with cached web pages. Log out of TurboTax. Clear your browser's Internet cache. Close the browser and reopen it. Then log back into your account and try to download/print the prior return. Does it still ask you to pay? If so, please contact Support as DoninGA mentioned above.
