Legal Question in Consumer Law in California

There isn't a lot of information to go on here because you didn't say why they won't give you the money back or why they haven't done the work. Talk to the manager about the situation. Give them a deadline to refund the money or do the work. If they don't comply, you can try small claims court if the amount in question is less than $10,000. You can also consider filing a complaint with the Better Business Bureau or writing a review on a website like Yelp.