Don't know if you clicked on the link in my earlier post. Cost per 2 tank dive was $120. How does that compare to what they originally told you? I expect it's the same, but I've always thought, how hard is it to post dive rates on their website.
I would try the email again just in case the first didn't get through. Not making excuses but it happens. It is a small resort, with one person who will be in the office to check you in and answer questions you may have. There is no direct number to the dive shop.
Not sure of your expectations for the resort, but you basically will just have your cottage (that's what timeshare/vacation club people get) that you are living in for the week. The only staff you will deal with during the week would be the office person if you have problems or questions. You will see a couple of waitresses and a bartender (they will know the names of people who do the AI) and a few maids. You will see and may be able to engage in small talk with some of the dive staff. Some nights, there may be a handful of divers hanging out at the bar. It's just a quiet place for the most part.
Although I linked my SB review in the earlier post, I am providing links to my TA reviews. The 2015 review was when Dive Tech (still my favorite dive op on the island - did checkout dives with them in 1998) was the in house dive op.
2017 trip
Cobalt Coast again; Reef Divers new - Review of Cobalt Coast Grand Cayman Resort, West Bay, Cayman Islands - TripAdvisor
2015 trip
All the reviews are right! - Review of Cobalt Coast Grand Cayman Resort, West Bay, Cayman Islands - TripAdvisor
Not sure if you said you were renting a car, but I highly recommend it. You had also asked about restaurants: Camana Bay has several. We went to an Asian place there around lunch time and found it to be one of our best and cheapest (they had a special) meals. If you happen to look at the TA links above, you can probably get to other reviews I have for places we ate and things we did.