Vitality flight booking on Kulula

Impossible to book flight tickets on Kulula using Vitality discount if flying with children not on the same Vitality profile. I tried booking flights for my mom and brother's children. My mom and I are on the same Vitality profile and my brother & his family on another. The eldest child is turning 15 so they refuse to book the 3 kids on their own Vitality number and just link them to my mom and I. I had to act as if neither my mom nor the children were Vitality members to get them booked. What a stupid situation!!!! Needless to say with 0 discount