The following is the letter from com2us informing me, that they trademarked the phrase "Tower Defense" and that I infringe that trademark with my game "Tablet Tower Defense"

Dear Sir/Madam:

I am a corporate attorney of Com2us Corporation (“Com2us”), which has engaged in developing, distributing and marketing a great variety of mobile games for worldwide customers. We are writing (1) to make you aware that your company is currently infringing Com2us’s trademark rights of “TOWER DEFENSE” mark in several countries and (2) to request your company to take reasonable measures to avoid further infringement.

We have recently notified that your company has submitted the mobile phone game applications entitled “TABLET TOWER DEFENSE” and “TABLET TOWER DEFENSE FREE” (collectively, “TABLET TOWER DEFENSE Games”) to the Google Play market and has provided the relevant service for operating these applications, which enable worldwide customers to freely download and play TABLET TOWER DEFENSE Games.

However, Com2us has retained exclusive rights to use “TOWER DEFENSE” mark in connection with mobile phone games, computer games and their relevant products in several major countries, as indicated in the following list of “TOWER DEFENSE” trademark registrations or applications.

(...list of trademarks, US, South Korea, Japan, China...)

Given TABLET TOWER DEFENSE Games incorporate “TOWERE DEFENSE” mark entirely into their title, your company would be subject to civil or criminal liability for trademark infringement in several countries as long as it continues to use “TOWER DEFENSE” mark as part of the Game title. Particularly, in U.S., if an infringer continues to use an infringing mark even after receiving a trademark infringement notice, he will be considered a “willful infringer” who may be liable to triple damages, including the infringer’s profit as well as the trademark owner’s attorney fees. Such use also constitutes trademark infringement as well as unfair competition in South Korea. Further, in Japan, a trademark applicant may seek against an infringer some amount of compensation equivalent to trademark license fees. Moreover, under Google Play Developer Program Policy, the repeat infringement of another’s intellectual property right may result in account termination.

To prevent further damage to our company caused by any such trademark infringement, we would like to request your company to take the following measures promptly: (1) change the title of TABLET TOWER DEFENSE Games to the extent that any such modification is sufficient to avoid trademark infringement of TOWER DEFENSE mark; and (2) modify or delete any contents of TABLET TOWER DEFENSE Games that display a mark, symbol, or logo including “TOWER DEFENSE” mark. If your company has any alternative to avoid trademark infringement except for the change of the Game title, please feel free to suggest it. We will use best efforts to reach a reasonable compromise.

To avoid unnecessary legal proceedings, please deliver your company’s response to our requests no later than 10 business days from the date of receipt of this letter. If your company is willing to comply with our request, please make us aware of a reasonable period of time necessary to implement the measures stated above. We will use best efforts to resolve this matter amicably.