I received an email from TurboTax stating that my 2018 Tax Return was wrong due to an error in Turbo Tax on Form 8960 Deductions. Tax Home doesn't show return. Why?

That's common to end up with multiple accounts. First LOG OUT of whatever TurboTax account you're logged into right now. Then use this TurboTax account recovery website to get a list of user ID's for an email address. Run the tool against any email addresses you may have used
https://myturbotax.intuit.com/account-recovery/

If you used the Desktop CD/Download program then the only copy is on your computer and not saved or stored online.

I suspect it's a scam.  TT does not let you finish if there's an error in any form.  

Once you find your proper account...not scam...

...here are the official TTX FAQs:.....with links to the directions for Online or Desktop users:

https://ttlc.intuit.com/community/tax-topics/help/2018-form-8960-deductions/01/843674