If your auto debit was setup correctly, no additional actions are needed and sending a check will result in paying twice.
If you set-up a payment for your income tax payment using TurboTax and you did not specify a payment date for the withdrawal, TurboTax's default payment date will be used (the last day of tax season = April 18th this year).
If your payment date has passed, but your tax payment has not been withdrawn yet, payment will not usually be not initiated until the return has been processed. Most states don't begin processing state returns until after the federal return has completed processing (your payment is still considered timely, as long as submitted before April 18).
You can also call IRS e-file Payment Services anytime at 1-888-353-4537 to verify your payment.
Contact your state Department of Revenue: https://ttlc.intuit.com/replies/3302452
OR
To check the IRS or state payment date selected in TurboTax:
1. Sign In to TurboTax
2. Select "Taxes"
3. Click "My Tax Timeline"
4. Choose "Some things You can Do"
5. Select "Download all forms and worksheets"
6. Review Part V of the Federal Information Worksheet for payment and banking information.
7. Review State Information Worksheet for payment and banking information.
** If the election checkboxes are marked "NO" and OR your banking information is not displayed on the Information Worksheet, then the direct debit was not successful. To setup payments for federal and state taxes, use the links in this answer and choose from the payment options available. If you did not set up your payment through TurboTax, visit www.irs.gov/Payments and choose from the payment options.