No, there is no way they will know you ignored their request.
Chat with our AI personalities
you cant
just tell them with who
If they say 'Inbox me!' or something like that they mean they want you to add them as a friend on facebook.
Simply go to the message section, type the name of your facebook friend to whom you want to send message in the 'to' box. Type the message and simply send it.
there should be a sign stating that a friend is trying to video chat with you