Only stick on outside of glass

So this is my second order from Stickermule and I was very happy with the first order. When I got the static clings I was surprised that the protective paper was on the back of the clings, but I checked the stickermule site and the video shows the clings will work on either side. I was wanting to use these in car windows, so I was relieved that they worked on the inside. However after sticking them inside my car window they would just fall off, but they worked great on the outside.