Did you have any other issues before they replaced the clock spring? Like the air bag light on, horn not working. I replaced my clock spring last year, "(not hard to do)" but they were more symptoms then just the cruise control not working. Well anyhow, if it was me I would first check to see if their was any fuses related to the cruise control. You can also check the horn/cruse control wire harness that connects to your clock spring, its right behind your air bag it could be bad. The cruse control switch does not cost too much... I did a quick search and found one from rock auto for $24. I did another search and found a good write up on installing a cruise control switch.
http://www.jk-forum.com/forums/jk-write-ups-39/installing-cruise-control-75351/