Are you sure that it is bent and not simply dislodged from its mounting holes (assuming that it is how it is mounted). There was no heat involved in banding it, so I don't think heat should be needed to fix it. Did you try to bend it back to the way it should be?
The other option, assuming that this will continue to be used as a ram for Hot Wheels,
would be to take a pair of cutters, or similar tool, and just trim the plastic so it no longer touches the rail.
