I also get repeated calls from this business despite asking to be put on the do not call list.  Calls are made from various numbers and as soon as I block one, calls come in from another number.  Often when I answer the phone there is silence followed by a dialtone.  I've informed them I'm on the Do Not Call list, they simply ignore it.  They also know my last name.  I asked once how they got it, and they claim it was "sold" to them by a supermarket.  They are breaking the law in several different ways.  I've never done business with them.  I even told them I already have a solar system, and they still keep calling usually in spurts based about a month apart.  I've reported the number to donotcall.gov and I encourage people to do the same.  If you feel it's a waste of time, the government won't pursue it if only one or two complaints come in.