I love my pixels and I've had my pixels taken and used for actual commercial use more than once. There's not much you can do unless you actually do decide to lawyer up. You can complain, you can send them Cease and Desists and all the typical warnings before you lawyer up but they all know the bluffs. You just gotta suck it up or spend more money than it's worth to protect just that one case and hope it doesn't happen again(and it will).

Welcome to the internet.