Should you call your friend to tell her that you are sorry?

Why, what have you done? If you've commited the wrong, then you should. However, if your friend has commited the wrong and is too stubborn and graceless to apologise, they are obviously not as clever or mature as you. You should then be mature and try to negotiate and make peace with them, and they will respect you and you will be friends again. If all fails, you should not consider them your friend anymore and give them the cold shoulder.