Do it right back to them. I spend weeks calling them back. I work a desk job, so it's easy. Ear phone in, redial. They get very angry and tired of answering with their long phrase every few minutes. They yell, swear, threaten to sue me, threaten to call the police. They eventually send me to their legal department and list all the charges "they plan to use on me". I tell them, I'm simply doing to them, what they do to me and countless others. If they plan on bringing me to court, they will have to justify why they are allowed to do it, and I am not. They usually hang up after that and leave me alone for a while.
I have had this phone number for 4 weeks and keep getting calls from someone who can't speak English wanting someone who I do not know. I think it is time to call in the HACKERS as no one from the Gov. is doing anything to stop these people.