That really sucks. I agree with asking GM for assistance on the repair because you really have nothing to lose.
As others have stated this is one of the big reasons I chose the Ram on my truck upgrade a couple of years ago. I plan on keeping my truck a very long time and I'm convinced it's a matter of when and not if the CP4 grenades and causes this mess. I have little doubt that trucks will end up being written off from this issue in the future because the cost to repair them will exceed the value of the vehicle.
I wish you the very best in getting your truck repaired and please let us know how it works out.