First call today...didn't leave a message

two calls in two days....first call, answered, no response on the other end.  Didn't even bother answering today.

received missed call from this number yesterday....no message left. When I called the number I got a message that I had reached a number that had been disconnected or was no longer in service. Today I received an incoming call from this same number and when I answered this, there was no response. Kept saying Hello and no response. When I tried calling it back, I got the same message as the previous day. Called my phone service provider and had this number blocked (just in case) also they noted that I had made return call attempts just in case there is some charge that shows up on my bill next month.