I keep getting hang-ups from this number every day, some times three times a day. They leave no message and I can't find any information about it.

frequent calls from this number without any message

Calls daily.  Doesn't leave a message.  I have blocked it.

Different people from the same number called and left a message.  One was female the first day and then the second time it was a male voice.  I did not pick up either call.  The message was as follows, "Hello? Is (my full name) there? I'm looking for (my full name)".

(604) 670-7559 - has called repeatedly for the last three days. No message.

I called this number back after it appeared on my call display (I didn't answer, and they did not leave a message). it is "voter outreach for Prime Minister Stephen Harper".

Keeps calling not leaving a message!  If you are going to call leave a message, if you're not going to leave a message, DON'T CALL!