Should I cut contact with this person?

[Alex]

I met a girl through Facebook in a one of those local groups, and we seemed to become great friends over the following two months, often meeting up and hanging out with her other friends, sending each other 50-something text messages every day, the whole works.

Well after 2 months, her contact with me suddenly in the time span of a week reduced down to about 1 text message every other day, and then nothing at all--not even a response to any of my calls or texts. Additionally, her Facebook profile vanished. It was a bit depressing, but I moved on. Well, after a solid 6 months of dead silence on her behalf, she suddenly contacted me out of the blue with a new profile. I asked where she had been all this time, and she claimed she'd lost her phone and my number with it. Considering the fact that she had both my email and Facebook link to contact me, I interpreted that as "I found a boyfriend and wanted to focus all my attention to him." Nevertheless, it was refreshing to see a good friend again, and I looked past it.

Well, again for about 2 months we became great friends again but somehow almost like clockwork, she stopped answering my text messages or calls (although this time she left up her Facebook, which I deleted from my list). Then after about 2 months of silence, she now sends me a text casually asking what's up. Honestly, I really don't want to talk to her anymore because I feel like I'm a "Buddy-for-rent" where she calls up to replace whatever major person it was that stepped out of her life, and then forgets about when she meets someone else (or gets back with him, one of the two). Do you think I should refuse to speak to her or let it slide and still be friends? I'm really on the fence about this....I just don't want to seem like a jerk if I were to refuse to have anything to do with her again.