Don't really know what to call it but it's between three people.

To give background on this story, I've been hanging out with my older cousin lately and he's been hanging around this one girl he knew from back in high school. I came to know her and we became acquainted.   So he ends up asking her out, which she says no to because she said that it'll "ruin their friendship" so he ends up telling me to ask her out. At first I'm pretty hesitant because I didn't want to cause any problems between me and my cousin, but after him insisting that I go out with her, i get her phone number.     Now this is when shit starts going south. Something he does is pick me up later in the day so we can hang out, and this girl has been involved with this for a while.      So one day when he comes to pick me up, I don't answer his text(since it was on facebook) but I answer the girls who he is with(her message was on from messages). At this time according to the girl, he flips out once he sees that i messaged her and takes her home and yells at her while ignoring my calls. This goes on to happen a few more times.         Despite all of this my cousin keeps on insisting that I should ask her out, so I do. We set up a date, but about an hour before it's time for us to go out she texts me, saying that her dad got into a crash and that she can't go out because her and my cousin were going to check on him. I say ok and set up another date 2 days later.         On the day of this next date she says that she can't go out because my cousin said no and "that if any thing happens to her while she goes out with me , to not call him for help" I didn't even know what she meant by that, but I didn't even bother to set up another date seeing that she cancelled the first date.         She ends up asking me if I wanted to hang out Friday to which I said sure because she "wanted it bad enough" to set it up. An hour before she cancels again saying that she has to go to the grocery store, and asks to hang out saturday. I tell her nah I'm good seeing that all she does is cancel. I go out with some other girl saturday. She ends up texting me several times to see if I'm willing to go out Sunday or Monday, so I say fine to Sunday.         Come Sunday morning she hits me with some cousin-excuse-bullshit. At this point I'm fucking done, I text her that I don't want to deal with none of this cousin-cancel bullshit. She hits me back with this massive text telling me to go fuck my self, it takes every bit of will for me to not fire back. My cousin calls me later that day and tells me not to talk to her anymore because she is a crazy bitch.

TLDR: cousin introduces me to girl, and tells me to ask her out, I ask her out, she cancels a shit ton of times by saying that my cousin doesn't want us going out. This leads me to tell her that I don't want to deal with her bullshit, and she ends up texting me a large ass text telling me to go fuck myself.

Should I respond to her text? Do i get mad at my cousin? Did I handle this situation right?