Refund of advance money

I booked a restaurant for a celebration on 2nd October paying a token advance of Rs. 5000/-. the celebration was for 8th October. I realised late that they had quoted a higher price as told to me 2 days back(30th sept). Basically, they quoted 650 bucks per plate and when i came to enquire, and the quoted 800 bucks citing increase in price 2 days later when I booked it. As I was tired of finding new places, I gave in and paid the advance amount. Now, I cancelled the reservation a day afterwards on 3rd October citing some problems. The person said that he is going to talk to his manager and call back. My question is: 1) what are my legal options if they say that they cannot or will not refund the full amount. Or they will refund only part of it? 2) they have not given me a receipt for the 5k I paid as a advance either. It was my bad that I didn't raise it as I didn't even think twice about the sales pitch they did on the price front. I trusted them and walked away. Please suggest the legal course considering the worst. Thanks. Regards Kishore