If it's not valid, why was this ticket not disputed and/or closed?
Not really a fan of the “failure to sufficiently deny an accusation is an admission of guilt” line of thought.
Maybe they’re getting a legal opinion. Maybe they’re leaving it open while they talk business to business. Maybe the right person to address the issue is on vacation.
Lots of people and companies choose not to engage in public battles. I don’t think that should be read as a sign of guilt (or innocence).
> Maybe they’re getting a legal opinion.
Acknowledging the issue is something you are looking into does not incriminate you.