If you chose to pay TurboTax fees out of the refund, and if your Fed refund has been delayed longer than normal (I think 36 days after the original expected date), then at some point TurboTax will send you emails asking you to pay. If you don't pay the bill, they will send you an email that they will debit your bank account. If you still don't respond with a payment or to ask for a deferment, they will debit the account.
One of the paragraphs in the agreement you signed for the payment method allows for that in case there is an unusual delay, or if the IRS reduces the refund to the point where it would no longer cover the TurboTax fees. Since TurboTax has no way of knowing whether or not you'll ultimately get your refund, they will bill for their fees.
If you can't pay, you should phone TurboTax Support ASAP and request a deferment, or they will ultimately debit your bank account. They start the process a couple of days ahead of the debit date. Once they start the debit process, they can't stop it.
FAQ: What is the TurboTax phone number? (hours 5AM-5PM Pacific; 8AM-8 PM Eastern)
https://ttlc.intuit.com/replies/3300041
