Is AUTHOR wrong in the post ? POST : TL;DR: I've had a chair in my room for 3 years that I own 33% of, my sister owns another 33% of the chair and wants it in her room. I refused.

I want to start this off by acknowledging that this is petty. Accept it and move one.

So, when we were young, my brother sister and I shared a computer, with a desk and chair to use with it. Over time, the computer broke and us siblings bought our own laptops/computers/tablets/whatever, so the desk and chair went unused for just over a year. I have had the chair for 3 years in my room, and I constantly use it with my own desk.

My sister recently took the old desk into her room and wants to take the chair with it. I made an offer that she takes it today (the 17th) and on Saturday (the 19th) we go to a local thrift store and buy a new chair. I can't go buy a chair myself because I can't drive, my sister does. She isn't available to go buy one on my Saturday schedule, so I offered to give her the money and go get one herself. She refused because she isn't available at all during the store hours (I call bullshit but can't prove it). She will not go get a new chair on Saturday, so I told her that I wouldn't give her the chair in my room and she stormed off all upset. 

There's two sides to this.

I have had the chair for 3 years, the previous year it was unused by anyone. So within the last 4 years, I've been the only one to use the chair. My sister's only argument for why she should get the chair is that it's not mine, I replied by telling that it's not hers either. I made a fair offer to give her the chair for a few days until we get a new one. I don't want to wait till the next Saturday (the next day we're both able to go to the store) because she probably won't be able to go then either (just a hunch, but I am very busy on Saturdays, I could only go in the morning). I also fear that if I give an inch, she takes a mile, she says it'll be for a while, but if I give her the chair, I'll never see it again. She's not reliable on promises like this.

&amp;#x200B;

The chair isn't technically mine, I'm just the only one using it and the only one who needed it until now. She technically has 33% claim on the chair. The chair was bought originally to go with the desk that's now in her room. She might have better use of the chair (I use it for gaming mostly), so she might be doing something with the chair/desk that's important, like work or something.

It's not exactly mine, but it's not exactly mine, so who's in the right here? Who should get the chair?