Trust me, corporate has 0 loyalty to the employees, even the managers, and they will threaten people into giving you want you want so long as it is not ridiculous and you have not cursed at anyone. No matter what a manager says before you call corporate, they will usually be pissing their workshoes the moment that phone rings after you dial corporate from your cell.
Protip:
Before going the corporate path start asking the manager for their card. Almost all managers have cards and are required to give them to a customer. The moment you're asking about that, the manager will know the direction its about to head and likely cave to your full refund or w/e you want.