Location/place: Bharuch

Name of company/service: Beverages

I have purchased 600 ml fanta bottle from Maruti hotel on NH no 8 near Palej, Gujarat. He is taken 35 rupees instead of 27 rupees which was printed on bottle. When i argued with him he was telling we are charging extra amount because of electricity. When i told him that i would complain in consumer forum them he told me you can do it.
Please take some steps.