I've never been on q-net but I got virtually stalked by a guy on another server for a long time. It started off really stupid, like in the chan he would follow me from chan to chan (/whoising my nick), then a couple times he would tell the op that I was spamming so I'd get kicked.. This sorta childish/stupid behaviour went on and off for a while. Then it got worse..
He began to nuke me till I got booted off irc. When I reconnected, if he was thier, he'd boot me again. I decided to get smart and learned how to protect myself from these so called nukes and even how to launch my own (though I never did.. I kept remember lines from movies about stuping to thier level).
What I did do though was keep acurate records of conversation exchanges and handed them over to irc "officials". It actually stopped for a while then one day he started again. So, I finally told a couple fellow geek buddies of mine to make him go away, and like Jimmy Hoffa, I haven't heard of him since.