to the state governament

1. You can check your state government,department of consumer affairs.
2. Go to www.yelp.com and give them a review
3. You might even want to take the store to your local small claims court.

Ask the store if they have retail permition (in california, it is called seller's permit). They are supposed to put the permit on the most obvious place. If they refuse, you can call your local city government and check to see if they have license to do the retail or not. If not, the local goverment will take care them.