I did this a year ago...used this guy:
Law Office of William R McGee - General Litigation - Rancho Bernardo - San Diego, CA - Reviews - Photos - Yelp
Piece of cake. You send them the background, receipts, etc. They draw up a complaint. Mfr has 30 days to respond...then takes another 30 days to get your money. Lawyer gets 4k...THAT is not related to your buyback. Mfr HAS to pay that. this guy says he serves ALL of Ca. Good Luck!