It is difficult to know what is motivating your ex. Perhaps she is deliberately hurting you. Maybe she misses you. She might also not have been fully aware of what she was doing the night that she was intoxicated.
The issue may be that you too easily allow her back into your life. From the few examples provided, when she contacts you, you respond immediately. You don’t have to do that. Your reaction essentially gives her permission to contact you when she wants. You may be allowing the contact because you love her.
One possible solution is to stop all communications with her. That would be an understandable reaction given the way she has treated you. From an emotional perspective, it would also be a psychologically healthy reaction.
If you are willing to allow some contact, then set the parameters of the relationship. In other words, you set the rules. Blocking her on Facebook is an example of you setting the rules of the relationship. Not taking her calls or responding to her e-mails are two additional examples.
A good “rule of thumb” to remember, with regard to relationships, is to treat others how they treat you. Treat them no better than they treat you. Treat them no worse than they treat you. If you continue to struggle, I would recommend seeing a therapist. Therapy can’t take away the emotional pain associated with the breakup but it can help you to recover from it. Please take care.