They started calling but leave no message. I will block them on my phone

Got a call from this number this morning.  The phone rang, but only went to one handset so I was unable to even take the call.  ( I picked up a different handset but the phone kept ringing.)   Phone rang several times this morning --- lucily I did not pick it up.  Weird!

They called yesterday - no message.
They just called again, I answered, a woman said 'hello', I said 'hello' then she hung up.
I immediately called the number back and got a message that said 'this number is disconnected.'
Bizarro!

We have the same problem - same number calls every day at the same time but they hang up when we answer.

they call the same time every evening, say one word and hang up.