Hotel Akasaya
Extra Price on MRP

When im travelling between hosur (Tamil Nadu) to Krishnagiri (Tamil Nadu)

i bought a britania Good Day in which the actual MRP is INR 10.00 but they altered the price in the biscut cover as INR 13.00 and i paid for that and i requested for bill they refused to give it

Please help me in this how to complaint officially

Hotel Akasaya (its a small hotel where goverment buses will stop for the break (which is illegal), close to Krishnagiri)