Friend Problems

I honestly don't like my friends that I have. They aren't supportive of my sports or my family. They leave me out of things and claim it is because I am always busy because of my sports. I know that if it's 3 friends, someone is bound to be left out, but it really sucks. I tried to stop being friend with them before, but they told my parents and I was forced to make up with them. How am I supposed to let them down easily that I don't want to be their friend anymore?