Nobody in telecom wants to receive ten faxes from midnight to 5 a.m. every day from some spammer selling Viagra, but making it your mission to hunt the perpetrator down and take legal action is counterproductive.
Resolving a harassment call (like the repetitive fax call) can take as little as about 24 hours if you simply report the offender to your local phone carrier and let someone else do the hard work. Carriers can find the call, track it back to the long-distance carrier that originated it, and have the long-distance carrier force its customer to stop bugging you.
You can prevent some of these calls from dialing your home by listing your phone number in the National Do Not Call Registry. This is only an option for residential phone numbers. You can find out more about it at www.donotcall.gov/default.aspx.
Your timeline is completely different if you decide to sue the person calling you. It’s a long and painful process that may or may not yield results. Rather than relying on the honor of the carriers to help you (which isn’t hard to work with) you are investing yourself in a legal system that must allow for due process and could take months to accomplish the same thing.