Bill payments are sent to payees based on the information provided when you setup the payee.
First, login to Online Banking and go to Bill Pay, then view the payee to see the address entered for the payee. Verify that this is the correct address (please be sure to check with the payee). If it is not, then update the address so it will be correct for future payments.
Second, contact Support by opening a ticket with the details of the payment, such as the amount, the payee, and the date of the check. From there we can provide guidance on next steps.