I don’t feel you’re in the wrong here. By the sounds of it, she was playing mind games. Honestly, it seems like she liked the attention you gave her and she knew by doing subtle things such as liking your posts, it would keep you interested to some degree. That’s really not a very nice thing to do. If she felt her and her boyfriend were too different, that is something for her to deal with before encouraging other people. Essentially it sounds like, you gave her the attention she perhaps felt she was lacking in her relationship.

If she really wants to contact you, she’ll find a way. If you unblock her, chances are she’ll continue to do the same thing.