If you have an insurance policy with a company that goes out of business, your policy is likely to become null and void. You can try to find a company that will take over the policy, but it’s unlikely that they’ll be able to do so.
If you were to get into an accident and the insurance company went out of business, you would still be able to file a claim and get your car fixed, even if you didn’t have insurance with that company anymore. The funds would come from the Motor Vehicle Accident Claims Fund, which all insurance companies pay into.