If you own a trademark you are under a legal obligation to protect that trademark.
As much as American lawyers would love to wage legal warfare, its your understanding about both technology and trademark law that is lacking here. A trademark doesn’t provide you a carte-blanche right over the name to keep suing anything and everything thats called Kik. It has a narrow band of applicability, in this case mobile apps for instant messaging. As long as the developer wasn’t building any such thing, you don’t even have a case to begin with.