The same thing happened to us on our first trip to Florida. The stop screw that is to small to stop the door at the rear of the pocket broke, and the rear rollers fell of the rail, caused from the jaring of the door against it. The first door roller close to you has to be removed from the door by flipping a white plastic clip and slide the rollers pin away from the clip, now the door can be swong sideways while the access to the derailed rollers will be accessible. The roller on the front can now be rolled pass the rail on the left side looking toward the kitchen. Now you will have to remove the rollers on the right side from the door and then reinstall it by inserting it in the same rail area as you just removed the left side rollers. Then install it to the door holder and repeat the same with the left side rollers
Now I feel you have no way to stop the door because the reason the door fell of the rails is the stopper that failed. I created a bumper stop with a 2 x 8 x 12" long that I had handy at the time and pushed it on the floor of the pocket till is it stoped at the back wall. I also tied a wire that I had in my toolbox at the time and now I can pull the stopper out anytime. But it has been working great for 2 years, so for me why waste a good thing.
Good luck, I never needed tools to reinstall the door, but had to put a screw on the stopper block to tie the wire. I feel that just pushing a stopper on the floor and using something later to pull it out might also work.
P.S. I just removed my door and puller the stopper out in order to check the lenght of the stopper and the procedure to repair. Now I am going back to install mine in again.
Just put the door back, tha stopper can be a piece of 2 x 4 as well but the door will deffinitly never fall off again as I tried to do mine by hitting hard and it is still good. I pushed the stopper with the door to the back and the door is just far enough to be able to grab the finger hole, its a little further back thae before but we like it like that, it makes the passage just a bit wider.