Of course they can. They can raise your rates for a host of reasons at any time. Plus, they didn't have all of the information on the car (VIN #) when you bought your policy. If the rate you have now is unacceptable, you should shop around for a one. Is your car financed, or did you pay cash for it? If it is financed, you may be in violation of the terms of the loan by having such a high deductible. When I bought my truck last year, I financed it through Bank of America. I read in the loan agreement that my insurance deductible could be no more than $500. You need to find your loan agreement, and read the terms.