I really do feel for you Yauhen, I recently had *exactly* the same problem with my main domain. In my newbieness I did not realise the guy registered the very first domain I bought to *his* name and not mine, it was a son of a bitch getting him to send the appropriate forms off to nominet (the UK version of ICANN to a degree) even after I paid the cocksucker the £100 he wanted to 'sell' the domain I had already 'bought' back to me. I was lucky and got everything sorted, but it was a long and painful time of not knowing whether I'd lose the domain, so I really do know what you feel like doing to this guy.
I'll agree with Sir Moby here - if he's close by give the guy a good hiding. If not then just store the info in your brain - you'd be surprised how life has a habit of putting you in some very nice positions a few years down the line
