I would hate to give you advice on how to do it yourself and have you mess up your bow and void your warranty. The best advice I can give you is go to a good auto or tool store and buy a good set of allen wrenches that fit snug when you put them in an allenhead screw and you won't strip out anymore.
Can someone from Support please tell me what size/thread that particular allen head screw is ... I don't want to send this back just to have one screw replaced... That just seems kinda excessive!
I can't provide you with specific advice, but...
I had a similar problem with a grub screw on my daughter's pressure button (recurve archer). Her pressure button is from Europe and has metric-sized components. I was able to get an imperial size allen key in the head and loosen it that way. It took very little force to get the key in, and so worn was the head that the imperial key felt like a pretty good fit! This might work for you, but you're in the US, where metric allen keys could be at a premium.
Have you applied a "loosening" agent, like a very light oil - in Australia we have a product called "Penetrene".
The only other things I can suggest get increasingly messy, and I'm loathe to offer them.
The first thing I do when I get a new piece of archery equipment is visit my local engineering store, and get replacement bits-that-might-fall-out-or-get-damaged.
Without knowing what tools or skill level you have available, this is what I'd recomend. First take it to a dealer or someone in the know, and let them fix it.
But if thats not possible.........
It looks like you have the PSE type cable guard clamp (as most Martins did for the last few years) spare assemblies are readily available (contact Martin or dealer, phone numbers on this website). Have a spare ready before you start the next step.
Using a hand drill or slow speed cordless drill and a drill bit that's smaller than the head of the screw, but bigger than the allen key size. Drill carefully into the screw head, when the drill reaches the the bottom of the head of the screw, the head will pop off. Carefully tap remaining screw until one side of the clamp falls out. turn over and push the other side out.
If your lucky you may only have to replace the screw, but I'd personally have the entire clamp ready just in case.
Install new one, Don't over tighten, use a quality set of allen keys.
If your not confident to do that, and I'm nor suggesting you aren't, then go back to to the first step.
Give our Customer Service a call (509-529-2554) and ask them to send you a BP-59 Cam-Lok.
you can drill the allen screw and get a e-z out which is like a tapered drill bit with left hand threads. this should bring it out. most auto parts or hardware stores have them. you might have to grind the end of the easy out to get it to fit snug in the hole you drilled. good luck