Other Fuel System Hoses Lines/piping, And Fittings problems of the 2003 GMC Envoy

My service engine light came on and then I started detecting a odor of gasoline. The order grew stronger and then I got the "special notice", but not a recall about the corrosion in the fuel tank. When I took the car into the dealer, I was told that this was not the problem and that it was a crack at the filler pipe on the gas tank and that this was not covered. I asked what could cause this and they could not give me an answer. My car only has 49,000 miles and is in excellent shape, except for all the recall items. I believe that GMC should fix this problem, not only it is costly to fix, but it is very dangerous to be driving like this. And reading the complaints, it sounds like several others have the same issue.