register at donotcall.gov
tell telemarketer to put you on donot call list when they call
if you are on the list then remibnd them that they are breaking the law
ask for the callers full name, phone number, and name of organization. ask whether they keep a list of tthe numbers not to call. if the answer is no to any of these questions then you can sue them for 1500 under the telephone consumer protection act.
if you want to annoy them ask for supervisor and then demand that they send you a copp of their written policy concerning donotcall numbers, the law requires this
before they call say that you do not want them to call or an affilliated company
call 1800cutjunk for a copy of a book on how to sue them