Thought I'd ask here before doing anything. 

Friend had this party. I met this girl which I was getting along with well. Started making out and some guys were cockblocking and saying she had a boyfriend. Thought they were all shit so I took her outside and continued. Was fingering her when her sister came outside screaming and she said she had to go.

Same party happened again a month later. I was sitting on the couch when that same girl came over to talk to me. I talked to her for a little while then started making out. I then invited her outside and we had sex. This was a normal sexual encounter. 

A month later, a third party is about to happen. One of the flatmates found it weird that I wasn't invited so asked the host, who said he does not want me to come. Found it strange but accepted it.

A couple of weeks later (now) I see the host, who I was friends with, and ask what that was about. He said the girl told him some things and about a lack of consent which he believes and no longer wants to associate with me. I said that was really fucked up and he said he doesn't want to hear my side of the story right now.

What do?

My current plan is to message her and ask to meet up to talk and then record the conversation on my phone. I don't know if she would agree to meet up, or what she will say in the recording. I don't know how many people know this.