Pairing multiple remotes for Aqua Marine Blue Drive power fin

My wife and I recently bought two Aqua Marine power fins, but we have been unable to make the two remotes set to different frequencies. Consequently, one remote Controls both rigs. We have tried pairing them at the same time and at different times, both together, and 20 meters apart, but nothing works. If they are 10 to 20 m apart, the remotes will both pier to the battery they are close to. But as soon as we bring them together one remote takes charge of both batteries, and the other remote does nothing. The manual specifically talks about the need for pairing remotes when there are two rigs working together, but I have done everything in the instructions, and it does not work. Has anyone made two of these remotes work with two different batteries?
Any ideas?