I answer they hang up.

Missed call.  No voicemail

Answered and they hung up.

Called my cell #, left no message.

Have gotten four calls from this number, both on my landline and personal cell, in last month. I don't answer, and they never leave voicemail except: the most recent time, calling on my cell, I got a voicemail that sounded like a very noisy room, like a call center, but no one came on to address me. the voicemail ended after about 30 seconds.