Domain Hijacking? : Domainer Cafe – Domain Forum of Domainnews.com

I’m new to this forum and message boards in general, but I need some help.
I tried to register my company name as a domain name, but someone already registered it. That’s not so unusual, but they used my contact information for the registered owner and admin info. I don’t know how they got my info, but it made me suspicious. So, I went to the website and the website has some weird script on it with one of my other domain names as the logo / header. I don’t know if this is identity theft or if someone is prepping to hijack my domains, but in either case I feel like I’m being violated. I traced the registrar back to Melbourne IT and sent them an e-mail to find out who is the real registrant, but no answer.
Can someone tell me what’s going on here? Is this guy going to try and hijack my domains? How do I find out who this person is and how do I get them to stop using my identity and my domain names as a header/logo?
Thanks!