Mechanic took serpentine belt off during smog test. Said part is no longer made.

What is your question?

I was given a car. Have to transfer from OH to CA. First step is to get CA smog. Mechanic said it was sitting too long & I'd need to drive it. Computer wasn't recognizing oxygen sensor. But while talking to him, it made weird noises. Mechanic removed what I think was the serpentine belt. Found compressor was damaged. I can live without air conditioning. But he said -- the problem now is -- we can't replace that belt because it is no longer made. I saw the part on-line. Mechanic put the old belt back on. He told me it was dangerous to drive. I'm not sure what to do next. Can the belt be replaced?