Why do they keep calling,  but never leave a message.  Don't call if your not willing to leave a message.  It makes you look like an Idiot and irritates people.  Some of us are busy.

They hang up after 2 rings.  Must be a probe of some sort.  I get about 4 calls in a row (every couple of hours, every week day) from odd area codes that are spam.  This is one of them.

Only rang twice, left no message.