Yep, that's all she can tell you, "take it to the dealer." But armed with your info, she will have a Ford rep contact the dealer service manager, and that rep will throw the BS card on the service manager and it will get fixed. This is the type of BS that can harm a dealer's relationship with Ford and, and the dealer principal won't want that. Safety items like air bags and seat belts carry different warranties and huge liability for both the dealer and manufacturer. Ford will fix it, usually cheerfully.
The other option would be to go to another dealer, which is probably a good idea based on the way you have been treated.