Check what policy your themes platform has on DMCA requests. Most likely they are required to take down your theme even if the DMCA request is "bogus". You might be able to file some sort of counter arguments with your platform, but till they file a request and the platform takes it down, you should feel free to ignore it. DMCA requests are directed at the platform, not directly at you.
According to the DMCA, in order to avoid potential liability, the provider is supposed to take down the content "expeditiously" upon receiving a notice and not restore it for 10 days, even if you file a counter-notification immediately. In theory, someone knowingly filing a false claim is then liable for damages, but good luck collecting on that.
In practice, though, the one time I sent a DMCA notice to a hosting company, they tried to mediate between me and the site owner rather than immediately taking anything down.
Note that as far as I know, non-US companies will usually comply with DMCA requests.
"Note that as far as I know, non-US companies will usually comply with DMCA requests."
No they won't if operating outside US jurisdiction. As a UK hoster we won't and don't recognise DMCA requests. We'll only remove content upon a receipt of a properly filed request/complaint by English lawyers (I work for a company registered in England).
There is no 'DMCA institution', further issues are handled in US courts assuming that the theme marketplace is operating under US jurisdiction. Read through the DMCA FAQ at http://www.chillingeffects.org/dmca512/faq.cgi paying attention to the notice, takedown, and counter-notice sections. Other countries may have similar mechanisms but details are likely to be quite different.
Assuming that the theme marketplace is in the United States and that your competitor does file a DMCA, you have the opportunity to file a 'counter-notice' with the service provider (theme marketplace) asserting your work is original and that you have the right to distribute it. The service provider is supposed to restore your original work in 14 days unless whoever filed the original DMCA notice brings a lawsuit in court. Whoever files a DMCA notice may be liable for damages incurred by the takedown.
- Forward the email to your theme host service. They're the "DMCA institution" you'll be dealing with.
- Ask them what steps are necessary to restore in case it does happen.
- Ask them if there's anything they would like at this time to prevent a long takedown / restoration process.
If everything is as you claim, it's possible this is a common issue with the complainant and the final straw to force them to leave the service due to a pattern of harassment.
