This sounds really strange to me as a parent of three,
in the beginning with ds1 I may have got into a battle about something like this, but now with my current 2yo I understand what to do.
First off, how many 2.5 year olds understand the concept of sorry? Mine is 2.2 and doesn't have a clue. He just has needs and wants.
Secondly letting them cry for an hour is really unproductive. You are probably really stressed and have little energy to spare, but distraction works like a dream. You just have to offer a chocolate button, or wave something they'll be interested in under their nose and the problem is forgotten especially if they are actually just hungry or something.
Honestly making it into a stand off isn't doing you, or her, any favours. All these odd posts about not giving in are bizarre - it's one sided if that's what you're doing. She won't be thinking, 'aha! I can outwit/outlast mummy if I cry for long enough'. She is just fed up. 
Why do people always think little kids are trying to manipulate them? They have feelings they don't understand or know how to handle so we have a duty to manage them for them. In the kindest way we can. I know it is tough with no energy but tbh it isn't going to go away if you assume she's capable of and/or attempting psychological warfare. She simply isn't.