Refusing to pay claims due to late registration on pregnancy benefit

I have been on a Discovery medical aid for +- 20 years. So I would think that I understand how the scheme works. I fell pregnant in August and my savings were depleted. I didn't know I was supposed to activate the pregnancy benefit. This I realised when I wanted to activate the baby benefit in September. Now Discovery is refusing to pay any claims (blood and doctor appointments) prior to me activating the pregnancy benefit, which is ridiculous because they can see from the doctor's reports / blood results that I was pregnant in August already!