What should i do about these 'friends'?

[Wrenn]

This one kid I've been friends with for forever has changed a lot lately, and now all he does is smoke weed. If he hits me up, it's just to ask for money. It's always the same thing, he'll text me or DM me on Twitter and then if I say I don't have money he starts badmouthing me on Twitter and talking s*it with a mutual "friend" about me also on Twitter. The thing is, I really dont want to hang out with them anymore. But if I stop responding to them, they start calling my house asking for me. They will also come to my house and rev their car really loudly in the middle of the night or stand outside throwing stuff at my window if I don't talk to them.

Itt's a stressful nightmare and I hate it. What can I do to get them out of my life?