The poster should be able to see the information you listed on their phone bill, whether wireless or landline. No subpoena necessary.

Thank you this is helpful. I actually did exactly that, including photographing my caller id screen for each and every call that's come through. Unfortunately, even despite my letters to Defendants' Counsel, the calls continue. As this is a personal injury case, I'm not sure that these specific actions (the repeated phone calls) would fall under any of my current causes of action, so I was wondering if there is a specific cause of action that would accomodate such bizarre behavior should I want to amend my complaint? Do you think I could seek an injunction in an instance such as this?