Changing therapists can happen for many reasons, and starting with a different therapist doesn't negate any work or progress you've made previously with an older therapist. What we have to do though is realize when a situation has run its course for whatever reason. It could be because we've simply reached the threshold of what we can accomplish with a particular therapist. It could be because one or both of the parties has changed (as relationships change and individuals change) in a way that makes maintaining a healthy working relationship impossible. Staying when the relationship is no longer working (in therapy or in real life) creates pain, anxiety, additional crisis, etc. Sometimes we have to know when to move on and find healthier relationships/situations for our own self-respect and sanity. Hanging on in the hope that one will get an apology and/or satisfactory closure simply continues to expose us to that unhealthy relationship. The fact is, some people simply will not ever change or apologize or give us satisfactory closure. To hang on waiting for something that just may never come just keeps us in a constant state of crisis with that individual.

I hope you can find that place within yourself to move on, even if the ending is not what you would like it to be, remembering that your need/desire for therapy is about internal growth and health. You can continue to work on your personal goals and healing with a different therapist; this therapist is not the only one out there, and this is a therapy relationship that seems to have run its course and is no longer healthy for you.