I understand your decision. I also have stayed at BCC and I have high regard for them. However, I do notice that the note attached also showed that one of their responses to you WAS from the email address that you used. So, even though I see the point of the others with their address.....seems as if BBC used bluecave@jamaicacw.com to respond to your deposit. One would think that if that address was used to respond and accept your deposit....then it would be answered by that one also.
Now, if you heard back from them regarding the deposit on another email address, then maybe that could be it. With your documentation however, I would be put off by no response. A copy of an email can speak volumes. I have, in the past, had resorts not honor the room that I had reserved 9 months in advance. They wanted to move us 3 times. It took a copy of the email to have a room without moving and it still wasn't the one I reserved. Emailing does have its advantages.
Good luck and have a wonderful time in Negril where ever you may stay. Peace mi brotha....