Ex-bestie causing me stress!!

meg 💛 • Expecting #1 with my wonderful husband after a MC 🌈 EndoWarrior💛
okay ladies, need some advice!
I have this friend, we were really close for about a year and have recently stopped hanging out as much because she just wants to party all the time - which is fine! - whereas I have "grown out" of partying all the time. she also will cancel plans at the last minute and never really puts in any effort to see me. 
We have begun arguing because she thinks I disrespected her, that I'm a bitch to her and I don't care about our friendship - which is not at all true. everytime I try to explain myself she just keeps bringing up old stuff and making me sound like the bad guy. I used to be a bit of a push over but now I've had enough and am standing up for myself and it seems she doesn't like it! I don't think we will go back to being friends after this - which is fine by me because it's so negative and frankly she is a bit of a bully!
my problem is, she has owed me $300 for about 2 years that she always said she would pay back next pay (yeah right!) and she has some of my clothes, make up & my fiances dvds. I keep asking her to give them back but she ignores me (I've even offered to go pick them up) it's like she's holding it for ransom! 
I simply want my stuff back and was just not going to worry bout the money but now I'm feeling so annoyed and stressed that I am considering taking her to small claims court just so I can get my stuff back! what would you guys do in this situation? any advice?