Nedbank Insurance rejecting claim without receiving full Doctor report

I have Nedbank Hospital Plan Policy and submitted a claim. My son collided with an opponent while playing soccer and was admitted at a hospital. I then submitted a claim when he was discharged. There was a General Practitioner document which the Doctor needed to complete and he couldn't complete as he was on leave and would be back on Monday 15 April. On Friday 12 April, I receive SMS saying the claim is rejected. How is a claim rejected without full Doctor's report?