Are you a member at Penfed?
You should look into Penfed Platinum Cash Rewards Plus (5% Cash Back at pump)
https://www.penfed.org/Platinum-Cash-Rewards/Steps:
1. Join Penfed credit union ($10 fee and $5 Share Account)
2. Open Money Market Savings Account ($25 minimum)
3. Sign up for PF cash rewards credit card
4. Call them to make sure they convert your CC account to 'plus'
5. use your credit card at pump and you'd get statements credits automatically, no need to go online to redeem them.
$0 annual fee - what you waiting for?!? At 15k spend, this should put $750 in your pocket every year with no effort other than setting things up initially with penfed. You can add additional card members too if you like.