Who called from 7202545677

Received call today - caller hung up without a word.

Very few people have my cell, and this number keeps calling so,  I finally answered, and it didn't say anything, a recording says "that is not a valid extension" and hung up.  Now it will be blocked.

called bout half hour go. tried to call back. voice mail is full. don't know how to block numbers on my phone. voic

Received a call from 1-720-254-5677.  Did not answer and blocked the call.  If it's not in my contacts, I don't answer my phone.

pest!