do you think I have a case
Not really.
Michigan insurance law is pretty generous in allowing an insurance company to cancel a policy during the policy term for a variety of underwriting reasons.
In fact, Section 500.2123 (4) allows for the termination "due to reasons which conform to the underwriting rules of the insurer for that insurance."
http://law.justia.com/codes/michigan/2015/chapter-500/statute-act-218-of-1956/division-218-1956-21/section-500.2123/
The claims, potential claims, and condition of your property no longer qualify for the insurance policy.
It's remotely possible that your insurance company is wronging you, but I think not, and your time would be better served by contacting an independent insurance agent who can get you insurance with another insurance company.
Yes, under the circumstances, you will pay more for the insurance than you have been paying but you don't have much choice. If you have a mortgage and you don't get a new policy in by the cancellation the mortgage company will put their own insurance on just the house and increase your payments to cover it. That insurance will not protect your personal property or your liability for injury to others.