@ cwilss
Under your question above it shows "Online Deluxe" for your product, but since you said "I bought TurboTax Deluxe for PC for 2018", that makes me think you are referring to the 2018 desktop product, but indicated the wrong product version above.
If you DID buy the 2018 desktop software, that does qualify to unlock all prior Online returns, but you'll have to notify TurboTax Support about your purchase and ask them to unlock your prior returns. The two versions do not "sync" with that information, so unlocking is not automatic in that case; it requires Support intervention. i.e., you should not have to pay for 2018 twice to get the 2017 return.
If that's your situation, you can use the form at the link below to schedule a call back, or it may provide a number. Hours are 5AM-5PM Pacific (8AM-8PM Eastern) Monday-Friday.
Where the form asks what product you are using, be sure in the dropdown menu to indicate "CD/download" and the proper operating system, then indicate which Edition.
https://support.turbotax.intuit.com/contact
