Indian Railway Catering & Tourism Corporation [IRCTC] — water vending machine at chittorgarh

Train 22901 reaches chittod junction and i go to the water vendor for 1 litre of water.. He confirms that i don't have my own bottle... Says it would cost 10... When i say the cost is 8 he points to another fellow who says don't have change.. On pointing that they are giving change to others he says drink some water and would refill for 2 rupees.
Why i as a consumer have to ask for the right price to be charged 3 times