I assume you are referring to the plastic clip which holds the bottom edges of the seat cover to the frame. They are general referred to a J-clips or J-strips.
They are very common for breaking away on the ZR seats, and there are several options for sorting the problem:
The simplest way is to drill through the plastic and the metal plate it fits to and use self-tapping screws to hold it in place. However, the screws can tend to break through the plastic eventually, leaving you back at square one.
A better (but more involved) solution is to replace the broken clip. You can either get a used clip from a seat in a breaker, or see if you have a vehicle upholsterer in your area who might sell you a suitable length (or lengths) of new J-strip which can be stitched to the seat cover in place of the damaged one.
