Some company is after my name!

Just received a mail from Apple that a company, Nexon, feels I have infringed their trademark and am unfairly blocking their game on the App Store by using the name novaWARS. If you Google 'novaWARS', all you get is me. If you search for 'novaWARS' (or 'nova wars') on game databases, you only get me. There are a couple of 'nova wars' games already out there, none of which seems owned by Nexon. So I'm somewhat confused what IP I'm infringing.