Typical Teenager Troubles

I've been away from Mibba for quite some time. I was mildly confused when I logged on to find that everything was different. I'm slowly getting used to it though.
Ahh, how I've missed Mibba.
For tonight, I would like to share a few brief thoughts.
I have been unable to sleep for the past few weeks. One of my friends has accused me of something without knowing the full story. Even though I know that I'm not in the wrong, I still feel terribly guilty, and that guilt has been keeping me up all night. To say I'm tired would be an understatement. I'm most upset that instead of asking me about it, he chose to yell at me. Oh, and when I say he yelled at me, I mean he sent me a harshly worded text message, because that is the level of maturity that he's currently at. He's unable to actually talk to me about what's going on, so he has to discuss it over text message. I've tried calling him, but he ignores my calls and only responds to my text messages. So I responded to his harshly worded text with a very sarcastic "Oh, I'm so sorry." and left it at that. I'm unsure as to whether or not he caught the sarcasm of the text, but I'm almost positive he thought that it was a genuine apology. It wasn't.
So, here's the decision I'm currently facing:
Should I just give up on trying to fix things with him? I know he's not going to put in the effort to fix our friendship/relationship, so if I want to fix it, I have to do it myself. I'm not sure if I want to fix it or not, though.
Should I try to calmly explain my side of the story so he understands what really happened? This seems like the obvious solution, but as I mentioned before, he won't answer my calls. If I were to tell him the whole story, it would probably end up being a 15 page text message and that just seems a little ridiculous to me.
OR
Should I yell at him in return? (And of course by "yell at him" I mean send him a harshly worded text message.) I already typed out the text that I wanted to send him, (only two pages instead of 15) but I lacked the courage to actually send it. It's a very well-worded text message that's sure to make him feel even worse than I currently feel. I think sending it would make me feel better, but I'm not sure if I really want to make him feel bad. He was my best friend at one point.
I want to be the nice person, but nice girls get blamed for everything. I've learned that over the years. I'm so sick of people walking all over me, and this time, I want to stand up for myself. I just don't know if it's worth losing a friendship.
Feel free to give me advice, or share any similar situations that you may have experienced. I need all the help I can get. Since I didn't really say what happened between this boy and I, feel free to ask if you'd like to know more.
Thanks for reading!