Oh MY! I'm so sorry that happend. Make sure you contact your states department of weights and measures to let them know about what happend. They need to come check this guys tanks. I hope Carlos is honest and does come through for you. I know this is a real pain. Was this you usual station? Maybe he is as much a victim as you are.
We used to have a station in Albany where this was a common occurance. After a while it became common knowledge that your taking a risk filling up there. They would "fix" the problem then bang, it would happen again. After a few years the state shut them down. Sure the gas was cheap but it wasn't worth the risk for me.