My ex is mad at me over this... what should I do and why is my ex mad for?

He is mad because I ignored him and didn't wish him happy birthday because I stopped talking to him He plays games with me. Cancels everything important to me. My acting performances at school, my birthday, valentines day, etc. He only texted me happy birthday. Then when I confronted him about all of this. He ignored me for two weeks. So we broke up and I told him I was going to do the same thing. So he had his siblings call my phone asking how I am just because I did not say happy birthday to him because he kept cancelling last minutes each time my birthday comes.