GEMS termination of members without consent

I joined Gems in 2014, last year I added my younger son to the medical aid. I was told about a 3 month waiting period while the premium was increased to includw him. After the waiting period, my son was sick I took him to casualty only to realise that his membership was terminated without my knowledge and I had to spend R2000 fromy pocket to have him treated. When I called Gems for an explanation I was told that they sent me an email to confirm if I want to add him on the medical aid (I didn't receibe that email) . Why would I pay for him during the waiting period when I want him terminated? I was told to complete another form and be subject to another 3 months waiting period.