If your refund is not forthcoming from the IRS, you'll receive a Request for Payment email, which includes instructions on how you can pay your TurboTax fees (minus the Refund Processing fee, if any).
If you do not pay your fees within the time frame specified in the email, you’ll receive 2 additional Account Debit Pending reminder emails.
Finally, if your fees are still unpaid 45 days after your original
estimated refund date, TurboTax will debit your bank account for your TurboTax
fees and you’ll receive a Debit to your bank account has been initiated notification email.
Note: If the IRS releases your refund after you've
paid your TurboTax fees, TurboTax won't deduct your TurboTax fees twice.
However, they will still deduct the Refund Processing fee, if any.
See this FAQ:
https://ttlc.intuit.com/questions/2552376-what-if-my-federal-refund-isn-t-enough-to-cover-my-turbota...
