First off, I would call her back on your terms.... or if it were myself I would go out of my way to not call her in the time frame she requested.

Secondly, you are in the right. Your contract said a minimum of two weeks and you decided to give a month. I would tell her no and not make a conversation out of it as there is nothing to discuss.

I hope this all works out for you. This is a crummy situation! Good luck