Sorry to hear about that Wendie, but we do have both screws # RRB154 & # RR89UB available for replacement for the Rhino-Rack 2500 Series Legs for Vortex Aero Crossbars # RRRLKVA.
There is no secret to getting the screw out, but since it's stripped it's going to be a lot harder. If you have enough of the head removed, you can try using a set of locking pliers around the head and back it out that way. I've actually had to do this a couple times, it's not fun, but it works. view full answer...