I havent' here in OK but in other states I have. Start by calling around to the local shops and just ask them if they can service a chiller. I can tell you for sure, it shouldn't cost more than $50....if it does keep calling around. I eventually got a company that had father time for a mechanic working there. He had my 1/4 chiller charged up and ready to go in 30 min. He didn't give me any "well i don't know if i can do this" he jumped in and said sure thing. He read the labels on the chiller that told him how much to put in and went from there.
Anyway, sorry for the rant. Good luck with the search. If you can't find one just sell your halides and go led. LOL.
Jason