Next day - Call from dealer service center

I got a call the next morning saying that the fuel is adulterated, they have taken the sample fuel. They said it would cost me about 5000 rupees to clean up the tank and change the filter. I was not told of any procedures, protocols that have to be followed, I have not been told as to what would happen if that diagnosis was found incorrect or insufficient, I was not told as to what it would cost me or what parts would be affected if the car doesn't work by cleaning up the tank. I was told that there was a mix of petrol in that diesel.