Sorry to hear that you partner did not enjoy his experience. As you correctly state during the briefing we show you how to act under the water and use the equipment including if you get water in your mouth. Again as you state if your partner panicked and forgot all of these instructions the instructor will help you to the surface. Once at the surface the bouyancy control device keeps you afloat, so there would be no reason for your partner to be grabbing hold of the staff. As you state your partner asked to get out of the water so was assisting in doing so, once out of the water the instructor returned underwater to assist other customers. Also as you stated the dive time you completed was 40 minutes , you where clearly briefed before the dive picked up and dropped off at your hotel. We asked your partner if he was ok once the dive was over and he expressed his disappoint over not being able to complete the dive and there for having no photographs, we no not dwell on divers who ask to get out of the water, especially when everbody else in the group completed the dive. As for your aggressive phone call to me ,when demanding a full refund, I clearly stated that you had booked with Viator and would have to contact them direct. You have not once mentioned the fact that you completed the full experience yet you still expected a full refund. You also booked on a group tour, if you wanted a 1 to 1 experience that is what you maybe should have booked.
Thank you