Who called from 7701892472

Call received on 09/12/13 @ 1:59 p.m.
again on 09/18/13 @ 10:12 a.m.

Could answer, called back immediately, call couldn't be complete

Received call on 9/26/13 at 1:10PM.  A recording said "Goodbye."  I called back and got a recording saying call couldn't be completed as dialed.  Very frustrating.

Calls come from this number repeatedly. Upon answering, a recording says, "Goodbye," and the phone hangs up. Seems to be phishing for valid phone numbers.

received a call and when returning it was told couldn't be completed. who is this ?