Fair or not fair?

I lent my sister my old handphone for more than 6 months now.. She said she want to buy my old phone.. But guess what? She WON'T buy it eventually

She barely even touch her guitar so I used it and put it in my room..

I kinda owe her around RM50 from my hair dye(She's not using that Garnier dye either, so what's wrong for me to have it?) and some stuff.. (but I recalled lending her some fares for the taxi she took when she went to work.. I don't think she actually remembered it..)

So here's the problem..

Just now, I told my sister of a proposal of exchanging my phone with her guitar, since she's not using it anyway.. Then she went SOOOO overly angry and said I still owe her this and that, and that she won't be using my phone forever and so on.

Then I said she's taking things for granted, as she's using my phone for half a year and she's throwing it back to me now. What a joke! My phone still worth around RM130 at shoplots and her "more than 3-4 years worn-out-string" guitar doesn't worth much as well. (she bought it around the same price also, excluding the bag.)

I told her about using my phone too long and now she just return it to me like that? She just take things for granted. she took 6 freaking long months(and more to go) to repair her SE phone? And to say that she actually has another phone that she can use(A touch-screen phone that looks similar to Iphone, some ciplak phone) but she insist on using mine!

This ain't a good deal? I had a digi prepaid and I gave up on it because I don't have another phone for it. Now the sim card's gone for good. It's expired and MIA

Now she said she's going to give back the phone to me and ask me to leave like that? And to pay her RM50 back? And she's not even trading her guitar for that?

1) I didn't said anything of not returning her her RM50.. but yeah I never remembered those thing though.

2) I never even asked her to change the guitar string using the new string her admirer bought for her some 2 years ago. I can buy some cheap string that my guitar teacher said and that will just do fine.

3) Talking about money, I did mentioned that I used quite some money to buy Korean Dramas.. But when I asked her to share, since she's having a part watching it.. She'll say no.. If she took the share for it.. I've already cleared my debt. But sadly everything turned out the opposite way.


Who's got the fairer idea? Mine or hers?

P.S: I just want that guitar so that I can start training it after school holidays in the Music Society. But it seems that I should buy 1 myself then. My dad will eventually scold me then for wasting money on another guitar.