That isn't a blend door problem. Its a problem with the main vacuum supply line coming from the engine. Defrost is default so that if the vacuum supply is cut off, the window will not fog up. If it worked fine before the blower switch recall was done, then something happened while fixing it, and the dealer should take responsibility for it.
It is not necessary to remove the glovebox to perform this repair. The blower resistor and connector are easily accessible from under the dash without going through the glovebox. If it was the switch and connector in the control panel that were replaced, chances are good that the vacuum control lines were not hooked back up to the climate control panel, which would be the dealer's fault. Keep arguing with them until they fix it.