Is there something that someone gives craiglist another persons pH number and craiglist calls that number to give them a PIN or code to set up an account?

If someone gave out your number, then you can explain the mistake to Craigslist if they call. More likely, someone is just pretending to be from CraigsList to get some account information from you.

Bottom line, some you don't truly know has called you. Say "wrong number" and hang up.