I'm one to easily burn bridges, so I don't know if my opinion counts, but you should just block her everywhere since you can't just ignore her and wait for this 'friendship' to cool off. Lock your visible profiles if you wish, make it look like it isn't personal.

I feel like I've been two-faced in friendships before because I needed support or something. I was nice to them, but I didn't consider them to be close and neither wanted that closure while they seemed to consider me bffs.