If the duplicate payroll taxes go through, it will result in a tax overpayment. Just follow the steps and details in this article to troubleshoot the issue: Resolving a tax overpayment.
If you can't void or delete the duplicate transaction, I'd suggest contacting our Payroll Support Team. They'll pull up your account in a secure environment and help you with this one. You can request a callback from our support agent so you won't have to wait on the line.
Click the Help icon on the top right.
Tap the Contact Us button at the bottom.
Enter a short description of your concern.
Choose Get a callback to connect with our support.