If you live where there are underground lines then you will be able to ruin someone's phone life very easily. All you must do is go to their house and find the green junction box that interfaces their line (and possibly some others in the neighborhood) with the major lines. These can be found just about anywhere but they are usually underneath the nearest phone pole. Take a socket wrench and loosen the nut on the right.
Then just take clippers or a sledge hammer or a bomb and destroy the insides and pull up their phone cable. Now cut it into segments so it can't be fixed but must be replaced (There is a week's worth of work for 'em!!