Impostors who claim to be from Google or associated with Google (they are neither). They either claim your business Google+ profile is not complete/verified or that they can raise your search engine rankings through their adwords and SEO services. Today they tried the SEO angle with me, but since they call multiple times a day from different spoofed numbers, in about an hour I’m sure they’ll call back again from a different number and try the other angle. They spoof numbers from all across the USA to avoid being tracked and blocked. They try to make you believe they are from Google (or that they are associated/partnered with Google) to persuade you to purchase their bogus services so they can obtain your financial info. They call all numbers (including cell and Do Not Call list numbers), and they hang up if you ask them to verify their identity, their company, or ask too many probing questions. They are looking for an easy mark. They call me at least 3-4 times every single weekday, and it's been going on for over a year now despite my number being on the Do Not Call list. My number is always robodialed by them, and they rarely repeat the same spoofed number so they can try to bypass any blocking you've setup for their other numbers.