Before you go to bed, unplug the phone. Unless you wanna bother with fileing a police report (if you live in the US) for harassing phones and then have them request your telephone company to put on a tracer and then they can go get this person.

Cons:
You have to do a lot of footwork and paperwork before anything gets done.

Pros:
Unplug your phone and sleep peacefully/turn it off