Hotel Selling Aerated Drinks almost double than MRP

For celebrating my marriage anniversary I am going to JungleHood, Karandi. After lunch we order 1 Aerated Drink which is having a price 40 rupees but they charge 69/- rupees when I ask about that they told us that they charge extra for aerated drinks, almost they charge double for aerated drinks.They are not giving me a any reason for extra charges. After final billing they also add service charges, My question is very simple if they collect service charges then why they also charge extra for aerated drinks and other.

Atul Zambare
Pune, Nasrapur 412213, Maharashtra
Email: axxxxxxxxxe@gmail.com