Called but did not leave a message and no CallerID.

Called again, and once more left no message.  This is at least the 4th time they have called since I first logged their call a 3 or 4 weeks ago.  I have not been able to identify who this is, but the fact they never leave a message seems to indicate they have no legitimate business with us.

I have received calls from these people on Oct 20, 21, 22, 28, as well as today.  I have no idea how many times they have called me prior to my noticing them on Oct 20, and logging the call here.  If it is a local call and caller ID doesn't show anything, I will frequently ignore a few calls if they don't happen too often, on the off chance that it is someone I know, and so that I don't fill up my Call Block (max of 250 numbers blocked). But no one I know has told me they tried to call, and I doubt that anyone who knows me or done actual business with me in the past would call multiple times over a two week period and NEVER leave a message or tell me in person that they had tried to call.  So I think its pretty clear this is either an unethical Telemarketer (ignoring the DNC registry) or a Scammer. (A Charity or Political caller would likely leave a pre-recorded message).  In any case, they are now blocked.