Rear Seat Belt Buckle problems of the 1998 Ford Explorer Sport

I spoke with 3 other mothers that have 1998 explorer and on each the middle seat belt won't work, I have three little grandchildren, and because of the problem I could not take all three anywhere. They could not seat up front. Why do 4 out of 4 1998 explorers have the same problem? at first I thought I would just order a new one, but I didn't have the $80. 00 for part and installation. Upon talking to these other explorer owners I really felt that inferior belt buckles were used. My dad was a Ford man and we were Ford people. Please help.