what are the first 5 digits of the number ? - I might get to region / circle with first 5 digits, after that .you would have to speak with your service provider / take legal action
hit him/her back with 1k missed calls too or if not, then if you have a close friend in that company, he might be helpful in that revealing his name (unofficially)
Which phone? Maybe they have, but in India, no phone has it. IT IS ILLEGAL. Why are you people so bothered. Just activate Call Filter or Add it to your phones reject list. And give them a load of missed calls from PCOs.