^ I'm not sure what you mean ny grille backing. Once you take it out there is just an empty hole in the fender. Sounds to me like it must be coming in half like I described. That is not the way to remove them and taking two halves apart while still in fender is a lot harder then taking apart once whole thing is out of car. What ru trying to take them out for? Did u buy just a replacement front half?
If there is plastic behind what you are taking off / separating, it isn't coming out properly.