Who called from 4064379034

I get a call from this number about once a week and it always hangs up when I answer???/

5 times in half an hour and when u pick up no one is there

I get several calls a day from this number on my business line and no one is ever there when I answer.

A man from this number 406-437-9034 called our office today asking to speak to the person in charge of oil & gas magazine subscriptions.  I told him the owner was not in, he said he would call back.  30 seconds later, he called back with the same line.  I told him we just spoke a few seconds ago and he hung up.

calls about 15 time a day and no one says anthing