call all times of the day, would like for it to stop!!!

I have been getting calls from this number NON STOP for 2 days. ALL DAY LONG.
NO one is here to answer the phone..SO instead of simply leaving a message, they
hang up and call every 30 minutes..My caller ID regrstry is FULL just from this number.
This is rediculous! I was going to call and tell them off however, naturally you can not get through from the outside!  I do not think it is a bill collector
since I have no outstanding bills..I am also on DO NOT CALL REGISTRY! That never stops them though....

started calling two days ago will not leave message