New friend won't hang up and I don't know what to do.

I got a new job where everybody is 50+ years old except one other girl who's my age, so we started hanging out and we became friends. She's a cool person and I enjoy her company, but the thing is, she always calls me on the phone and will not hang up! It's getting so annoying, honestly. She will call me every day at night and start talking and talking and talking. I can't even say anything because she talks non stop. We haven't had a call that lasted less than 30 minutes. After a while, I get tired of listening to her talk non stop and I try to get her to hang up. Once or twice, I've used excuses, but I can't do that all the time, because she'll know and it's rude. Sometimes I tell her that we've been talking for a while and should probably hang up and she'll agree, only to keep talking. Even when I remind her and tell her that we need to hang up, she'll say yes and then start talking about something else. She just won't hang up no matter what!!!

I HATE it! I'm not much of a talker and I don't want to be listening to someone I've known for just two months yapping on the phone for 1 hour. I have stuff to do. I know I probably sound rude right now, but I'm so tired of this. Sometimes I just don't pick up, but obviously, I can't do that every time, because it's obvious and kind of rude. Honestly, I don't know what else to do. I tell her every time, but she ignores me and keeps going. Any advice?