Thank you for posting in the Community, Shelly_L.
For the vendors that are being notified of the scheduled payment. In QuickBooks Online, We email your vendor twice to make sure that it was been received. The initial email will inform the vendor that you have arranged for a bill payment to be sent to them. The second email will let the vendor know that the payment is en route and provide an estimated arrival time for the bill payment.
We do not send notifications to your vendors in case of payment cancellations or failures. Please make sure to contact them directly if there are any issues with your scheduled bill payment.
For the suggestion of SIAB offering a third-party option, that would be an alternative.
In addition, you can visit this page to learn more about Bill Pay in QBO: Learn about QuickBooks Bill Pay for QuickBooks Online.
You can inform us at any time if you need further assistance with Bill Pay in QuickBooks. We've got your back and will respond as soon as possible. Stay safe.