Should I let an avoidant friend dodge tough questions?

This girl who used to be my best friend ruined it for both of us this summer. She is a very avoidant person by nature and is very hard to talk to in the first place. I sent her a message on facebook asking her why she was so willing to throw our friendship away, and she told me that she was too tired to answer the question and was going to answer it tomorrow which to me, knowing her, was an excuse to not answer the question at all or answer it in 3 days at the earliest, with her excuse being that she "never goes on facebook" (she's pretty predictable for an avoidant person). I complied, but when I left the conversation I wondered if should have just pressed her to answer it. Did I do the right thing?