Have you already seen this posting?
Don’t know, if this phone is still available, but maybe you could get the covers alone. 
Or you might find something to your liking in this thread:
E.g. Mitch 6 by Feuerwear
@Roboe
If I get it right @silkefph1 is looking for the “rubber”-cover and she for sure has a FP1, that needs protection (even more so, as spare parts are becoming extinct).
EDIT: adding a to show, I didn’t mean to hold it against roboe. I initially simply forgot this.