Calling For Months, Several Times A Day, Til Early Evening.  Asked To Stop, Keeps Calling.

This company Diversified Consultants calls me at 6:10 a.m. looking for someone I've never heard of.  I've had this cell phone number for over a year now.  I've received several calls for the same person.  i tell them whoever they're looking for isn't at this number, they have he wrong number, ask to be permanently removed from their cal list.  They assure me it's a done deal only to call back the same day asking for the same guy again.  how do i get them to stop?

Calls constantly (10+ times per day); never leaves a message. Called the number back and it says it's a company called Diversified Consultants. No live person to answer phone.