This app was mentioned in 1 comment, with an average of 1.00 upvote
You can pay with credit card using their E+ Mobile app. $4 - $5 fee for the average bill. Not sure if your rewards >= the fee.
https://itunes.apple.com/us/app/e+-mobile/id1087390302?mt=8
https://play.google.com/store/apps/details?id=com.talgov.eplusmobile