Epicure rooftop restaurant charging more than MRP

Went to Epicure this evening, and they charged ₹45 for a ₹20 Kinley water bottle. I asked the waiter, how you can charge morethan MRP and he says “humare menu me 45 rate likha hai toh utna hi rahega” I tried to reason with him, ki agar aap apne branding ki water bottle rakho it makes sense to charge 45 but how can you charge extra for some other brand. Talked to the manager also but eventually had to pay ₹45