Harassing Phone Calls

I have been getting calls from these lizards for months.  I am not in debt, I have never been in debt and I have no idea what this is about.  They call and ask for someone else and no matter how many times I tell them there is no one by that name at my number (which I have had for many years) they ignore that and keep calling. I called them back today and requested that they stop calling me - and they listened so well that they called about 4 hours later.  I have filed a complaint with the FCC and will make complaints to any agency that I can think of.