Shop charging extra as cooling charge

I live in peace road near eastern mall ranchi. In my neighbourhood there is a shop named Creamypoint. In this shop once I purchased a cold drink bottle of of Rs 35 and I was being asked to pay Rs 38 . 3 rs extra as cooling charges. I even refused by saying that MRP is Maximum Retail Price and charging extra cooling charges is illegal but the lady was not ready to give me the cold drink on the MRP printed on the bottle.Till now she charge extra charge as cooling charge on cold drink bottle.

shruti kashyap
Ranchi 834001, Jharkhand
Email: kxxxxxxxx6@gmail.com