Hi Flower,
I agree with Bunny. But if you do choose to contact her, you might just want to air out your feelings matter-of-factly, demonstrating self-respect and respect for her. Something like, "you know, I enjoyed the times we visited in the past, but as you say, you dropped me like a hot rock. So I don't know where our relationship really stands. I like you but the on-again, off-again stuff is confusing to me. What's up?" or whatever.
Doesn't have to be angry or hurt, if you are not feeling that way. But it is confusing. Maybe she knew you and your mom had a strained relationship and didn't want to get in the middle of things, etc etc. God, who knows? You seem like a pretty patient and understanding person, having let your aunt off the hook lightly in the past. Your choice.
I am not the best at keeping in touch and have probably hurt lots of people unintentionally in the process.

And there's no N lurking behind my insensitivity...take care, Seeker