Bests & Worsts Reviews from Amazon

I bought these in April/14 and have 3 left. For some reason they keep breaking on me. I fill them with filtered water, put them in the door of my fridge and leave them there. Well every now and then I go to grab a bottle and it's broken. Not all of them, just one. Today it happened again for the third time. I can't figure out why. If they were getting knocked around in the fridge then more than just one would break I think. I've taken the shelf out of the fridge to show you how it looks. If anyone knows how I can stop this from happening, I would appreciate it.