Baggage claim declined due to 24 hour rule!!

I took a flight to Johannesburg on 26 August and took out baggage insurance as added cover. My laptop got damaged whilst in the overhead storage and I put a claim in for the damage. Low and behold I was told that my claim can't be honored as I was meant to claim within 24 hours. Mind you when I landed in Johannesburg I went to a friend's place in Muldersdrift which is quite a distance from the airport, so even if I was aware of this 24 hour rule, I had no way to go back to Oliver Tambo. I was going back to Cape Town on the 31st August so I reported the damage as soon as I landed in Cape Town. I don't understand why the 24 hour rule is not stipulated when you take out baggage insurance, I'm not sure where in the terms and conditions this is even indicated. This laptop is means how I make my living and I'm really upset that this company can't do good on my claim as I took out insurance for this very reason. I've requested of them to send me a repudiation letter so that I can lodge a claim with the short term obudsman, I'm not getting any feedback from them!!