You aren't violating the copyright as the phrase "Weber" is only a key word , im guessing its one of the more commonly used search phrases at your website. I would just ignore their email. Secondly it looks like you site is blog-ish so you sort of have protection from legal action. Finally if your not making a profit of their name go ahead and use it , they cannot do anything to you.
they registered the letter "q"
i should register the rest of the alphabet and...