Insurance cancels me!

Hello first of all. I am insured with the Generali with part kasko with 150€ excess. I had a hail damage half a year ago and last month a wild damage. everything was unindebted. Last week came mail from the Generali (though it was my check for my wild damage) and Pustekuchen. It was the cancellation of the insurance without giving reasons until 03.07. My question is: Is the legitim or can they do that? If they are allowed to do so, I will have problems if ic h register with another insurance company? Thanks for the help