Claim not being honoured

Saturday 16 April, we realize our pool water had dropped significantly. Upon investigation, we realized that there was a crack on the wall of our pool. This crack was repaired before by previous owner of the house (we don't know details). We had purchased the house in October 2014. We called and logged a claim with Outsurance. Only to be told (after assesor had visted) they will not honor the claim, as it \\happened over time\and was not a result of a direct event... <br> What on earth do we have insurance for then\""