Once the IRS gets to processing the return the payment information will be used by the IRS to make the payment. TT only sends the debit info you entered to the taxing authority and has no other responsibility in the process. If you entered the correct banking info then it is up to the IRS to complete the transaction.
So was the extension successfully efiled ? And did you enter the correct payment information ?
You can access your IRS tax account for your payment history and any scheduled or pending payments - https://www.irs.gov/payments/view-your-tax-account
