How to fix bent gas tube?

[SideShow Bob]

If it was a 2 piece hand guard replacement rail, I see your point.
If it was a one piece free float rail, you are screwed for any factory warranty claim.

If this problem existed before you put the rail on, that should have been the time for warranty repairs.
But if the problem only manifested itself after you put the rail on in your attempt at being a weekend gun smith,
admit it man, you Bubba'd your AR ! And now you want someone else to fix your fuck up on their dime.