Get more money for C240 4matic then the insurance company offers? How to prove.?

Question by Global Express: Get more money for C240 4matic then the insurance company offers? How to prove.?
Does anyone know how to get more for 2005 Mercedes C240 4Matic then the insurance company will offer. They are currently offering $ 17,500. The fact is we bought it new for $ 45,000 and the prices seems very low. I can barely buy another at a authorized Mercedes dealer at the same prices. The car has 65,000 miles. The highest value I found was by Nada. Can I use the CPO price at

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