If you are unable to reserve your app name for which you hold the trademark or other legal right, or see another app in the Windows Store using that name, you may report the App Infringement at https://www.microsoft.com/info/Marketplace.aspx to start the following 4-steps process:  

  • Step 1: Contact information
  • Step 2: Application information
  • Step 3: Infringement information: You may identify up to 5 infringements for any of the following three categories:
    • Copyright infringement issue
    • Trademark infringement
    • Publicity rights
  • Step 4: Upload supporting files, sign and submit

Microsoft may provide your notice to third parties (including the alleged infringer). Notices of copyright infringement must comply with the Digital Millennium Copyright Act. You can find information on these requirements and Microsoft’s Designated DMCA Agent at https://www.microsoft.com/info/MSDMCA.aspx.