What do I do if a parking lot in a major city hasn't cashed my check yet?

I paid $9.00 for parking in a lot across from a theater in a major city. I wrote a check. I gave the check to a young man who appeared to be early '20s/late teens. That was April 9, it's the end of May, and they still have not cashed it. I googled the place I was told to make the check out to. I got an address for the owner of it. I was thinking of writing him a letter. (Only way I could see to contact him.)

Would that be my best bet?

I visit the city every couple of months, I was thinking also of swinging by there and asking whatever attendant happens to be on duty what I should possibly do or who I should possibly contact. I realize they may not know what to do either, but they may have a better contact number or address for me.

Ideas?

Nothing. A personal check is valid for 180 days. If they haven't cashed it by then, void the transaction.