I don't think you're overreacting. I returned a pair of pants to Loft because in the time it took for them to send the pants to me, the price was lowered and then raised again. I just took them back. And I'm not inclined to shop there again soon.
I've felt it's perfectly legitimate to take an unworn item back in and ask for the adjustment. I can understand that they wouldn't want to do it over the phone past a certain point perhaps, but with the unworn item in hand, in person, why wouldn't they? If they say no, you can decide then whether to keep it at your original NAS price or to return it.