keeps calling but leaves no message

It's a debt collection agency. They've been hammering my phone for weeks, yet I have nothing to give them, despite me telling them this.

I've been harassed with phone calls by this caller

Received call. No message left

This is a company called West Asset Management in Stockton, CA.  They are a debt collection agency.  I received calls also, but have no debt.  They are simply throwing a dart at a wall trying to find debtors on their list.  If you want to inform them they are calling the wrong number call 1-888-433-2886.  Call on their dime not the long distance number that shows on caller ID.