If you go to the Turbotax home page and click on "contact us" at the bottom, they now give a phone number instead of the complicated system they used before. You know the number is correct because the site as a secure (https) icon.
https://turbotax.intuit.com
If Turbotax thinks someone else has filed a return using your SSN, they can hold it for 48 hours before they have to transmit it to the IRS. But I don't know if this means all hours or only work hours.
This email could be a scam from someone copying a legitimate email and changing the phone number, so get the phone number independently from the Turbotax web site.
If you just filed your own return, this might be a false alarm, if you have opened more than one account with Turbotax. When the 48 hours is up, your return will be sent to the IRS even if you can't call in time.
If you already filed your own return, then this might be a case of identity theft. Even if the return is transmitted, the IRS will reject it, unless you never filed your own return. You will also want to change your Turbotax password, probably change the passwords on all your other online financial accounts, and start monitoring your credit reports. You may also want opt-in to the IRS identity protection PIN program.
https://www.irs.gov/identity-theft-fraud-scams/get-an-identity-protection-pin
