prank calls

I am getting so mad! For almost 3 days someone have been calling my cell on private of course, and when i pick up they dont say nothing,so today i picked up and was like "dont call my phone if your not going to say anything" and i hung up. Then less then 3 minutes later my phone rings again so i picked up and didnt say anything,so for like 20 seconds it was quiet,and all of a sudden i hear a deep male voice say "hello" and i was like "who is this?" and he said something so nasty i dont even want to repeat it! I just hung up..then they called back 2 minutes later,i didnt pick up. I understand its fun to prank certain people but to do 3 days straight in a row,dont the fun go away? dont you get tired of playing on someone eleses phone?