Saw missed call. Don't know how many rings. No message

Constantly calling me, they never leave a message nor is anyone there when I do answer. Unable to return call...it says the number is no longer in service. I have it on auto-reject.

Twice I have received calls from this number, one ring -- and gone.

One ring and done. I didn't bother following up.

My phone did advise it is a land line.