Has your internal battery run dry in Fire Red? Or has anything that does not belong been forced inside the cartridge at all? Because after a few years the battery inside the cartridges that are required for saving games will go flat and you will no longer be able to save the game.
I think that's what's happened when you said "Everytime I go back into firered it has deleted the game."
You can buy new batteries from any of those electrical shops and they're not very expensive (In Australia that is) I don't know about whatever country you're from but they should be similarly easy to replace.