You'd have to phone Customer Support and ask for the download. They can validate your purchase and push you a download.
Use the form at this link to be assigned a phone number:
https://support.turbotax.intuit.com/contactDo you already have an online TurboTax account? If not, you should set one up so they'll have an account to push the download to.
It's explained in this FAQ, which you may have already seen:
https://ttlc.intuit.com/questions/2590568-i-bought-the-cd-but-my-computer-doesn-t-have-a-cd-drive
