Indian Railway Catering & Tourism Corporation [IRCTC] — rail neer being sold more than mrp

In villupuram station plataforma number 4 canteen, rail neer is sold for 20 rs which is more than 15rs mrp. When asked they are saying normal water is 15rs which is not in stock thats y selling cold water for 20rs. Not sure how rail neer cost more than mrp only reason because its cold. If this is the case from how many customers they have sold the water and what are they doing with this extra money. Please investigate