I used to have the same prank caller for about 10 years and it was somebody I knew.
It started when he was 16, he would get drunk, ring up and start talking all dirty about one of my daughters.
The very first time I got her to listen on the other phone and she wrote his name & address down on a piece of paper.
After a couple of minutes I said "Hello Nick Smith who lives at 52, Victoria Road, Fenton, how are you?" (name & address changed) and the phone just went quiet.
He then came out with every swear word under the sun and put the phone down.
Two nights later he'd call again saying dirty stuff about my daughter and once again I would say his name & address and the phone would be put down.
A week later he started to tear into my wife & mother and once again I'd mention his name & address and he'd put the phone down.
It started to get less regular and I put it down to party nights so about midnight I'd get the same call and once again I'd mention his name & address but one time I was able to mention a jacket he had started wearing which freaked him out.
I couldn't believe that every time he rang he couldn't remember the previous phone call so I put it down to drugs.
The last time he rang I actually said "Nick, you must be 26 now, aren't you a bit old for this type of stuff? Are you still living with your parents Richard & Alice at 52, Victoria Road?"
That was about 2 years ago but I'm still waiting.