unwanted called from unknown person/company

I have been inundated with calls from several numbers:  303-974-1805, 201-257-4829, 410-774-8401, 617-245-9609, 202-747-7385, 866-581-2505, and sometimes no number is identified.  It just started right after Christmas.  I normally don't answer numbers I don't recognize, but I started picking them up today.  They ask for "Andrew" and I've told them twice that they have the wrong number.  Hopefully, the calls will stop.  I've Googled all of these numbers, and other people have tried calling them back and all the numbers seem to be related to the Career Institute or online classes.

202-747-7385, 303-974-1805, 410-744-8701, 201-257-4829. Just started yesterday and have already gotten 4 calls with these numbers appearing in caller ID yet each time I answered the phone, it was the same guy. He asked for my wife and didn't want to leave a message but he'd call back. He finally told me his name was Nathaniel and he was with Career Institutes. Very annoying frequency.

Got a call from this number (201-257-4829), the caller ID also showed CI. I called the number back...Career Institute. I pressed 1 to speak with an "Education Specialist". Got a human on the other end and told her to get us off their call list. She claims that she did but it will take a few days for us to come out of the system...we'll see.

Started calling 3 or more times per day. They are a leads generation/verification service. They get leads from internet ads that you would sign up to show interest in school/college. However, the "interest", like so many other adverts is very loose so that you will get calls even if don't remember specifically responding to a college advert. They first couple of days the calls are literally dialed by hand from more than one location so that more than one number shows on callerid. If after about 3 days, the hand dialing in unsuccessful, your number is transferred to the automated call center where their robodialer calls you daily. Basically, they just verify that you are indeed interested, then sell the sales lead on to more companies who then call you more. To get off their call list, call back any one of their numbers, and press option one to speak with someone. Just request to be taken off their call list, and they will do so.