Ex girlfriend still argues with me?

[john]

Basically my ex girlfriend broke up with me 3 weeks ago. And every week we get into a fight somehow. The first fight was me on twitter and she thought I was sub-tweeting and guilt tripping her when I wasn't, she got the idea that I didn't do anything after a couple of hours of fighting. A week or so later, we had another fight about rumors which I didn't say and she got the message I didn't do anything after another couple of hours of fighting. That same weekend she made her friend snapchat me to get information for some reason. We exchanged numbers after a couple of days and started to casually talk. Little did I know, that friend told another one of my ex's friends to keep it a secret that we texted. The other friend told my ex and I got into a fight because she thought I was also hiding it. She got the message I was unaware of what the other girl was doing. Consequently, my ex said she hated her friend for doing that. I was mad at her friend for getting me into drama I didn't need to be in, and stopped answering her texts and snapchats. Now today, that same friend, "said why are you mad at me?" and I told her that I was told she hid stuff from my ex and I got into a fight I didn't want to be in. She said it was bs, even though this girl is a notorious liar and was told by many not to trust her. I ended it saying that I trusted my ex more than her any day (my ex never lied to me, the breakup was caused by her schedule filling up and being overwhelmed with stress, not anything malicious). I just found out that my ex told her friend (which I thought she now hated), that I was mad at her and this stupid drama started. I never did anything malicious in our relationship, and yet she is finding excuses to argue with me, why is she doing?
When I don't answer her she comes up to me in school and starts the argument

[Gabriel]

just stop talking to her... simple as 123. problem solved and move on with life.

[?]

Ex girlfriends are nothing mate. Wait until you have an ex wife! Now those creatures are pure evil!

[Cnthia]

Because she still wants you and wants to keep in contact with you even if it is negative. Then again she is also doing this to you to keep you from being interested in anyone else. This is her way of controlling you even if she is not with you and like I said acting as if she doesn't want you. Look, unfriend her, change your number and don't talk to any of her friends and don't respond to her anymore, unless you like the craziness that she is constantly giving you. If not, just stop responding to the looney tune. She then will get the message.