Once a return has been e-filed through TurboTax and accepted, it can't be then deleted from the TurboTax servers. Maybe you used a different TurboTax account when filing other years' returns? In order to access your returns, you must use the EXACT login information (same username and password) that you used when preparing those returns.
See the info I'm linking below to help you recover your username and passwords.
Forgot your TurboTax Online user ID or password?