Be sure to bear in mind, unless they pawned off an assignmetn contract on you, that Sears is the party you contracted with (confirm this on your contract), and if so don't let them pawn the blame off on Malady - as their sub, it is their responsibility, not his (though he is subject to claims by them).
Pesonally, with all the investigations about fraud at the BBB, and news stories about vendors being able to buy higher ratings, I would forget about the BBB route, though I guess being Sears they might have some interest in keeping a good name on BBB. I would check into getting an attorney for this, assuming you have lots of documentation and written statements from the two roofers who said it was done wrong. If you have an Ownes Corning sstatement that it was done wrong that would crry weight too.
Guess you need an attorney experienced in homeowner contract claims - and look into whether Sears was licensed and bonded in your state (and city if required), because if required and they were not licenced as a general contractor and bonded if required, in many states that put them in the position of having to prove what they did was legal and adequate, instead of you having to prove they were not.