Can carriers raise your premiums for a serious accident where your car is totaled and the insurance company pays for your car but the insurance investigator ruled that the accident was not your fault?

yes if your ins.co. pays for your car. Even if they don't pay for your car. My agent warned me that my homeowners premiums could be raised just for filing claims! They used to send an adjustor out automatically if there was a hailstorm or windstorm, but not any more. I just wanted an ajustor to estimate the damage last spring and let me know if it would exceed my deductible.