tyre policy

I have a Insurance policy with Bidvest on my tyres. I went through a pothole in Bloemfontein and because of the pothole it damage my front right tyre with 2 bubbles on. I did submit a claim and just so that they can tell my my claim has been rejected because of the bubbles that was cause by the pothole. and now the refuse to pay my claim. The bubbles was cause by the potholes.. Why does one have to pay premiums and the reject the claims for any ridiculous reason.