Accident claim rejeted

I am dissapointed that Oldmutual rejeted my claim. The policy was opened and the insured individual passed on and the cause of death was accident. when i was on te call with old mutual i was advised that after completing my application all insured parties would be covered for accidental death immediately and covered for natural causes after 12 months. My cousin who was insured passed on a couple of hours after the policy was taken and Old Mutual rejected the claim. The contract between myself and old mutual states that for accident we were covered from the very same day we took the cover. Why is the claim rejected then?