Someone is stalking me through my iPhone?

So I was on this electronic exchange group on Facebook trying to sell an iPod. I post my number then this dude is messaging me trying to troll saying he's a crip and what not. Then he says where I live. Saying my exact location blah blah blah saying he's tracked me. How can I make it so he can't track me anymore? Or how did he even track me? What can I do just cuz I'm tired of getting trolled by this kid.

Added (1). Nah I don't want to call the police it's just a kid trolling. Just wondering if there's another way to solve the problem

Go straight to the police. If he is threatening you over text and etc.save them and show the police. Those threats are LEGALLY considered threats and he can be charged for them.

I agree with lost child you might not take it seriously or might be nervous but the police could be your way out of something bad id say the sooner the better

Block the kid's number. That way he can never disturb you.