Welcome to the forum from central Florida. So, one's missing and one is broken and the BR slide is open? First of all, you've got a couple of choices. Either haul it to a dealer and be prepared to leave it till they get a chance to look at it, or call a mobile tech and hope they know what the heck they're doing, OR, fix it yourself! I prefer the latter.
Reading posts about the cable slides, it's apparent that a whole lot of folks are needlessly intimidated by them. They really are not that complicated and it ain't exactly rocket science to adjust or replace them. One set of 4 cables controls the slide when its pulled OUT, one set controls the IN function. Each function, in and out, has 4 cables that do the "pulling" nothing is "pushed".
Now is the time to analyze your DIY skills. With some basic tools, and or course your favorite six pack, you can most likely "do it yourself". Like I said before, "it ain't rocket science". I always take the approach that if a human can build it, I can probably fix it. That philosophy is always supported by the fact that I probably can't screw it up a whole lot more than it already is, so why not try it?
I believe Amazon, for example, sells replacement cables. At least that's where I bought two when I replaced them on my previous rig. I would be hesitant about operating the slide with the problem you have currently. With two cables gone, you're putting more strain on the existing mechanism and could potentially shear the flexible drive shaft or strip out the drive gears, or even worse, cock the slide in the opening - not a good outcome there.
With all that said, take a deep breath and find the missing cable. It just didn't go "poof" and disappear. Its probably laying in behind the cable channel. The channel is held to the wall with probably six to eight screws. Once removed, you'll be able to determine. Now comes my favorite time of working on my rig - contemplating and Beer Break! I've found that replacing a cable is at best only a three beer job - unless my DW if supervising.
Once you find the end of the cable(s), it gets even easier. Just use the "Chinese Handcuff" that comes in the kit and pull the new cable through making sure you crimp the ends and route it through the correct pulley(s) - that's where viewing the Bal video might help. Do the same with the other cable. Once you get them where they should be, look up a post by
XRATED, I believe, that describes how to take adjust the cables. Excellent post and best read with your next beer break. Another must see is a
UTUBE video titled "7 minute cable slide adjustment" at
. This is exactly how I adjust mine. And finally, after the final adjustments, grab a lawn chair, sit in the shade and polish off what's left of the beer. You've earned it. Good luck and remember.....you can't screw it up much worse than it already is so give it a try! With some basic tools and mechanical ability - YOU CAN DO IT YOURSEF and save some $$$! It ain't that difficult.