Hi, Airbnb will block any links you add to a listing or send via a message to a potential guest as the system thinks you are sending contact details such as a personal e-mail address - https://www.airbnb.co.uk/help/article/1121/why-was-text-removed-from-my-airbnb-message-thread
I would suggest you provide some details of the content of the link in your description and state that full information would be provided if required once a booking has been confirmed.
Re contact - best to contact Airbnb via Twitter or Facebook, you get the quickest response via these routes.
Best wishes,
Ama