Calls once a day for a week.
silence on the other end.
When the number is called back there is only silence (does not even ring)

Got several calls from this number--have no idea who/what it is.  Very annoying since they are calling my job!!!

I have been getting calls from this # for three days now and no one speaks.

Same here--multiple times in a week. No message and nothing on the other end if I answer.

I also have been getting calls from this number, does any one know who is calling?