+1 on the labor board.
I wouldn't go in person. Just a way to start a very bad situation.
HOWEVER, I would send a letter, certified mail, return receipt requested. They can't say they didn't get that if you have the signature that it was received. In the letter, say that you are going to contact the Dept. of Labor. Find out who it is so you can be specific. That will get their attention.
While that letter is wending it's way to the company, call the labor board, dept. of labor or whoever is in your area. File a complaint with them. I don't think there is a time limit but you'll shore up your case a great deal if you don't waste any more time getting it filed.
Good luck and let us know how it goes.
--Wag--
unfortunately in california if you don't you haven't made every reasonable attempt. I'm not sugessting he go in there and raise hell just go by and say hey you know i think you missed a day could I please be reimbursed or something along those lines. If that doesn't work document it and go to the labor board.