Their trademark predates the .chat TLD (I looked it up on TESS). Nevertheless, your use is arguably different (this distinction matters under trademark law).

Their trademark predates the .chat TLD (I looked it up on TESS). Nevertheless, your use is arguably different (this distinction matters under trademark law). You're no doubt going to call the business (if it even is a business) something other than TINYCHAT, and are going to have a substantially different trademark. This is tricky (and IANAL), but I'd simply not respond if you are actually in good faith preparing a different product with a different market. Simply owning a domain doesn't make you a trademark infringer. There is no dot in their trademark (service mark) name. They could have included a dotted version in their trademark application, and they opted not to. In addition, to avoid further headaches with those people, consider coming up with a different name for your product, and simply redirect your URL to that different name.