that happens on mine too..bit of a tw@t to say the least..i actually took mine all out to clean it and ended up attaching velcro strips to the sides of the footwells and the carpet itself,didn want to glue it for when it came to cleaning it again
also make sure its clipped properly to the gold clips that are underneath your ?sill panel trim (i mite have made that name up
)-the black plastic thing wot sits on ur sill
Dinx