I have a friend in the USA who is planning to go to Pattaya in late December and he too wants to stay at the Ambiance. He also is getting no response to his Emails.
I have tried several times to call the Ambiance and I too get no answer. I have not been around Boystown to personally check, but since literally everything in Boystown is currently closed, I am guessing the Ambiance is also closed. There really is no reason for them to be open right now and nobody is going to stay in Boystown with everything closed.
I have no information yet whether the Ambiance will be open in December. If I am able to get any reliable information, I will post. In the meantime, I suggest considering a "Plan B". Part of the problem is we just don't know yet what will and will not be open in December. Don't forget, can open is a far cry from will open.