Ok, so if this can't harm your reputation then why can't you ignore it?

You won't be able to prove a negative anyway (that the TG chat didn't exist, or that you didn't send a message to the client). It's your word against Royse's, and since he's the one making the claim (about you messaging the client) then he should prove it. That's what I would state, perhaps without excessive name calling, and leave it at that. Anyone who can do 2+2 would see this situation for what it is. Opening new threads - like you did with the unsubstantiated forgery accusation - doesn't help you at all.