Who called from 4079247590

Called my cell phone and hung up.

Called at 3PM.  Hung up after I said, "hello" twice.  I called back and a recording said "This mailbox is full, try calling back later".

How do we get rid of the increasing number of calls like this one?

Called 3 times this week--in the evening--when I answer they hang up----Call back and their mailbox is full