I agree that even though she may not be using, she is a long way from working any recovery in her life. They say the real recovery begins when they leave rehab and use the tools they acquired there in real life. I don't know how long her rehab was for, but unless it is long term it is unlikely she did much more than detox and rest.
This is no reflection on you, not at all. She is behaving badly and owns her action regardless of her "excuses" for same.
Good for you for letting her calls go to message and then choosing whether you care to listen or not.
I'm glad you have found Al-Anon, and I know that these meetings will help you keep your balance through even the rockiest times.
Hugs