I used to work for the largest provider of bank bill pay in the US (contracted with ~80% of banks, IIRC). I would say that 95% of customers using the service h

I used to work for the largest provider of bank bill pay in the US (contracted with ~80% of banks, IIRC). I would say that 95% of customers using the service had no clue how it actually works. In fact, the default payment method of bank bill pay is to mail a paper check. Sometimes they cut a check with your account information, sometimes they will go ahead and pull the money from your account, but send a check drawn from their corporate account. Sometimes they mail the check 2-3 days before your payment date, so that (in theory) it has time to get there, sometimes not. The only time they send electronic payments is of the payee has set up electronic payments with them, and even then they may decide to switch your payment to a check at any time for any reason. What makes it even worse is that they try very hard to make sure customers have no way to tell how their payments will be processed, and there's never any kind of warning that something has gone wrong until you get a call about a late bill. For example, even your payment should be sent electronically, something as simple as a typo in the account number so it doesn't match the expected length or format might result in them sending a check to your payee (with the wrong account number), meaning that your payment sort of vanishes... Personally I always set up payments through the payee's site, using a credit card whenever possible. If they screw up the payment then it's their problem to fix.