Suzuki: 2000 esteem wagon, esteem wagon, service departments

Question
I cant put gas in the tank, canister, roll over protection devives replaced all vacume lines checked or replaced. service departments have no idea has anyone else ever had this problem? tank has been out three times and starting to get expensive.

Answer
this is just a guess, but - for the last fifteen to twenty years all cars have had a one-way flap at the entrance of the tank whose purpose is to prevent fuel from being pushed out of the tank from normal pressure when the cap is removed.  I've had to replace a couple of them about ten years ago when I was still working on cars.  The symptoms were the same....