Find out the oil company that more than likely owns the station. I operate a gas/service station. If something like this happened to a customer I would call the oil company that owns the station (the actual building and pump maintenance people). The operator of the gas station should know who that is.
If it were me. I'd suck it up and offer to pay for a new pair of shoes if you brought in the receipt, just to keep you happy and a customer and hopefully get your friends & family's business too. That's too bad that they can't see beyond the immediate $ outflow to realize the potential in being a GREAT customer service station. Then I'd call the oil company who owns the station (it's a sunoco station but the building and pumps are owned by Aranco oil) and demand they reimburse me for your shoes because their pumps were not in proper working order.
HA!
I hope you get what you deserve from that! Sorry about your new shoes!