This is cheating. No matter where you buy a car, purchase tax, travel tax and compulsory insurance are all necessary. As for the "service fee" you mentioned, there is absolutely no 4S shop. I suggest you read the car purchase contract carefully before considering how to protect your rights. If the amount involved is large, it is best to consult a local law firm.
Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.