Timing Tensioner problems of the 1998 Ford Explorer Sport

I bought a used 1998 Ford explorer for my wife and at 135,000 miles the cam tensioner broke, putting a hole in the valve cover and possibly ruining the engine. I called the local dealership, flaggler Ford. Ford's reply at first was, "yes this is a known problem and we will fix this at no cost to you". They towed my explorer in to the dealership and called me later telling me that while the time for this repair is not up, the mileage is over what they will cover. Ford said they would fix it for anywhere from $600 to $6,000! my mechanic, who told me this was a problem with these engines, said he will fix it for $300 plus parts. I have complained to the dealership and Ford costomer service, this got me nowhere, and a supervisor was suppost to call me today but as of yet. . . Nothing. After searching the net I found that I am not the only person who has had this very problem. Go to cartrackers. Com and you'll find a lot of people who have been taken by Ford for this problem. If I was the only person this happened to, well I would be ok with that but Ford's stance is that while its a defective part mine lasted longer than expected and that I get nothing but a bill. I have never seen damage to a vehicle like this before, and I have a Dodge and a chevy with over 140,000 miles on them and have never had a internal engine part fail and ruin the engine. Please help me and the other people who have been sold these vehicles haveing no idea that at any moment they may have to buy a new engine while the people who profited from these sales just sit back and do nothing. Had I known the life of my explorer was less than 100,000 miles I would have never bought a Ford. There was never a formal recall put out for this problem, just a service bulliten, so people who had these defective tentioners were never contacted. My guess is that Ford just hoped that the failures would occur after the 100,000 miles, and would just deal with the ones that didn't.