Who called from 7206067101

Called, did not leave message.  I have gotten similar such calls from a number that is the same area code and same prefix - 606-7XXX.  They never leave a message and if I block one number they switch to another.  I can't figure out who this is.

Called at 6:17 am, no one on the line.  Unable to match this phone number to any number we have contacted in the past.  Unable to determine who this is.

Called me at 6:41 am, voicemail was a series of beeps.

Showed as NETPROWA on caller ID. Called at 10:00AM, voicemail was just beeps

Received a call at 6:00 AM.  No one on the line - just a series of beeps.  I am in Lewiston, Idaho