Received call, didn't answer. Left no message.

Received a call, I answered, no one on other end.

called and left no message

If you pick up an actual guy tries to sell you a vacation package.  I hate getting phone calls on my cell phone at work!  Our elected representatives need to really crack down hard on these telemarketers.  It's easy.  Have a single opt-in database of phone numbers of every person who wants to give their phone number and who agrees to be called.  If your number isn't in that database, a telemarketer can't call it.  Conversely, there should be a list of telemarketers and their phone numbers that have been registered and verified (so authorities can go after them if there are abuses).  Have it set that your phone only receives numbers on that registered list (of course only if you've opted-in to receive such numbers in the first place) or from a number already found in your Contacts.  Boom.

Got 3 calls from this number in a 10 minute span.  Didn't answer, no message left.