Who to call when you get ripped off?

I ordered a car battery from 1-800-BATTERY. They were supposed to come to my house and install it. They never showed up. They did, however, charge my credit card $371. This is a legitimate business with thousands of positive reviews. They told me I'd get a full refund and that hasn't happened yet. I've called them 3 times and they say, "oops, we'll get right on that". It's been 2 weeks. Who can I call to light a fire under their butts? The sheriff? A lawyer?

YOUR CREDIT CARD COMPANY