Amazon India - Charged over MRP

I bought a **gb RAM form Amazon India (Order # ***-*******-*******) on Jan **, got it delivered on **th of Jan. To my shock, the MRP mentioned on the box was Rs. *,*** whereas amazon charged me Rs. *,***. I contacted the customer care regarding the same but they only gave lame excuses like the price might have changed and they simply refused to credit back the overcharged amount instead they asked me to return the product and get full refund. I don't want that, this is not first time that amazon/flipkart have sold above MRP but earlier difference was so minimal that I ignored (big mistake). These retailers don't understand the meaning of Maximum Retail Price, and take overcharging very lightly. In the past many Brick & Mortar sellers have been punished by courts of law for similar practice and probably its time these online retailers are taught the same lesson. Please find attached the box with MRP and Cloudtail (Amazon JV) invoice for reference.