Caller ID said "XXXXXXXXXX".  Clearly someone who doesn't want to be identified.

Caller ID said XXXXXXXXXX OK.  I never answer unidentified calls.  Rang 3 times and then stopped. Funny thing is the same thing happened yesterday except it was XXXXXXXXXX GA from phone no. 404-511-2897.  So I guess they can make it look like the call is from any state?

405-511-2897 called Sept 19, 2016 at 5:13 pm.  Caller ID = XXXXXXXXXX OK.  BLOCKED.
This is not the first call:
The XXXXXXXXXX SPAMMERS call again! Who are these idiots?
404-611-4009 CALLED Aug 9, 2016 at 3:50 pm.  Caller ID = XXXXXXXXXXGA.
Previous calls:
954-611-4009 called Aug 5, 2016 at 12:42 pm.  Caller ID = XXXXXXXXXXFL.  BLOCKED immediately.  Who are these XXXXXXXXXX callers?  Very annoying.
Previous calls:
770-611-4009 called Aug 3, 2016 at 5:44 pm.  Caller ID = XXXXXXXXXXGA.  BLOCKED IMMEDIATELY.
Been getter other calls from XXXX.... callers.
407-611-4009 called July 25, 2016 at 10:42 am.  BLOCKED IMMEDIATELY when I saw caller ID = XXXXXXXXXX FL
There are many others that start with the XXXXXXXXXXX and end with a State abbreviation like CO, CA, TX, FL, OR, PA and GA etc.
If you google "XXXXXXXXXX+calls", there is a lot of complaints.  No one answers these calls with a caller ID like this, so we don't know who or what this is.
Caller: XXXXXXXXXX SPAMMERS