The answer should be found in the policy itself. Insurance policies are contracts; they may only be canceled in acccordance with their own terms--i.e. for the reasons, with the notice, and when, cancellation is permitted under the policy. So the first things to do are:1) Read the policy carefully--including all the fine print and including any later addenda, modifications, etc. to the policy which you have received;2) Ask the insurance for "why" they cancelling the policy--or least for the specific terms or conditions of the policy which they claim supports cancellation.If there is no justification in the policy for the cancelation--or no answer that you find persuasive--the next step is to consult with an attorney, bringing with you the policy and all related documents or correspondence.