Dog taken off airplane instead of non live cargo

My two dogs were to be transported on SAA from OR Tambo to London Heathrow. Both dogs were loaded and then one was taken off after loading to make space for other cargo. Why split 'family' of dogs or not take off non live cargo. Transportation company was only alerted that my dog was left in it's crate much later that night and they fetched it to place in their kennel overnight to repeat the loading the following night. I had to incur further expenses to go back to Heathrow from the north of England again to fetch her the following day, cancel plans for that day as well as have a traumatised dog. SAA declined my claim of compensation saying that they removed her to stop her being harmed. This is a lame and unacceptable excuse. Why not then (still unacceptable as overbooking should not occur and this should not be done to an animal) leave a 'family' of dogs together and offload a single animal? I shall never be using SAA again.