I don't know what too do

I have someone in my life I really care for. She shows all the signs of someone with bpd and npd, we were in a relationship before she abruptly and without reason disappeared out of my life and was gone for 3 months before she contacted me, after she came back she was so angry at me for things I didn't even do, she will not even admit we were in a relationship. Everything I've read says I should cut all contact with her because they always try to come back but dealing with her at times it's like she completely hates me and I have never done anything wrong to her this is someone I fell harder for than I ever have before we are currently not talking but I'm worried she will try to contact me again and the way I feel about her won't let me ignore her even though I've never been hurt more by someone. So what do I do? for the longest time I thought I did something wrong and I am having a really hard time dealing with this any help would be very appreciative thank you!