Cavalier lock not opening

Hi, I recently pruchased a Cavalier CSS-96G coca cola machine.  I do have the original key to the machine but it will not open it.  The gentleman I bought from told me when he was a kid he over tightened the lock and has since been unable to open it.  If you could give me any advice at all before I call the locksmith that would be awesome!
Thank you

Sounds strange that the original key won't open it, overtightened or not. How did it get locked in the first place if it can't turn? I'd try picking it as that's the first thing the locksmith is going to do. I f you get it open you can take it out and try to get it to work, or just replace it.

Nate

Well what I ended up doing was drilling out the lock...Boy that took a long time, lol.  I started from the smallest drill bit and went all the way to a 1/2 " and it finally opened.  I then went to a vending machine distributor and got a new lock for $10.50.