man-in-the-middle

hey guys, I have just came from overseas and I had an incident with my car. The fuel gauge was showing empty althogh I have just filled the tank. went to the dealer and he told me that the fuel in the tank is a contaminated fuel (mixed with water, rust, etc and may be food lol ). He said it is gonna cost $2500. any ideas how to avoid that or any info about anything similar cheers, aa