Check the Where's my Refund tool or use the IRS2go app. If your filing isn't showing as received or accepted, that's why. You should receive an email telling you that it was accepted by the IRS if it's gotten to that stage yet. Otherwise, TurboTax gives a window of "typically up to 48 hours after" the return is accepted; if you still haven't gotten word after that, I'd call them.
I received mine after 40 hours, so best of luck.
TurboTax does not have access to your approval or denial, if you qualify for Refund Advance and are approved for the Turbo Visa Debit Card, you’ll be notified by email of the approved amount and you’ll be able to start spending online, typically within 48 hours of the IRS accepting your return.
You will be emailed instructions on how to set up your temporary Turbo Card account to start spending online.
Your Turbo Card will arrive in the mail within 5-10 business days. The temporary card information will work for 15 days or until you activate your physical Turbo Prepaid Visa Card, which will arrive within 5 to 10 business days of IRS acceptance and Refund Advance loan approval.
Please review the TurboTax FAQ below for more information.