We guarantee your bill pay for business payments will be delivered by the date selected, if the following conditions are met: 

• Your payment account has enough funds.
• All payment details are entered correctly.
• The payment is scheduled to arrive by its due date. 

If your vendor has not received your payment and it’s after the payment date, let us know. You can give us a call at 800-987-7237. We accept relay calls. 

To ensure it arrives on time, we recommend logging in at least five business days before your bill is due. For vendors receiving paper checks, U.S. Bank (we) use that time to cut and mail it. 
 
This doesn't mean you need to pay your bill ahead of its due date, only that you schedule the payment in enough time to arrive by the due date. 

See also, How to view the status of a check in bill pay for business.