Pack the whole thing up. Write a NICE letter explaining the situation. Don't be frustrated.. Send it over to Aqualung's Service Department and wait for a reply. Include a copy of your original receipt. They are pretty responsive.
I would think that a phone call first would yield better results. Just mailing in something with a letter may not have the desired effect.
I think the OP should call Aqua Lung's customer service department, and not bother with his "friends" at his LDS anymore with this problem. I am not convinced that his LDS actually called Aqua Lung at all regarding this situation. I would bet that if the OP called, and asked customer service to see if there's a record of his "case" (meaning: did his LDS in fact call in) - there wouldn't be. Just my guess...