Rear Seat Belt problems of the 2003 Dodge Ram 1500

I own a 2003 Dodge ram with about 46,000 miles. In less than 3 years I have owned the vehicle, all three rear seat belts have had a crack in part of the seat belt that prevents the belt from sliding when it is used to secure a child seat. The first 2 were replaced under warranty, but the third now will be replaced at my cost. Dodge has refused to assist in the matter, and they also refuse to recognize that the plastic piece they have designed to prevent the seat belt from sliding is woefully inadequate. The dealer I went to also was of no help fighting for the consumer. You would think that after three failures, a bulb would come on. Date of incident is approximate but after warranty.