Are you sure yours was stone and not paper KE
I got my stone years ago. I do not remember where I got it from, but it is at least 7 years old and has lived in my oven full time since I got it. I never take it out other than to brush burnt on crud off it from time to time. It gets heated up to 500 degrees weekly and goes through the self cleaning cycle anytime I run it.
Pampered chef stones are on the expensive side, but everyone I know who has had one raves about them. You can also go the inexpensive route and get unglazed quarry stone from your local hardware store for a few bucks and those will work perfectly.