I'm going to ask my ex not to consider me her friend anymore
Why don't you want to be friends with your ex anymore?
She disappointed me and wasn't being a friend anymore.
Sounds like you two need to separate. Often it's hard to be friends after a romantic breakup.
The plan is to ignore her until she goes away.
Your ex is no longer a part of your life and you should try to leave them behind. Let them know that it is time for you to move on and wish them the best future.