Cancelled an order before the order was shipped/delivered, company not refunding money.

I'm the director of Hankavalshier Food Products Private Limited. We were looking for a machinery for our business and we contacted Sakthi Automated Food Machine Company, Coimbatore for it. They sent us a video and a photo of the machine and a quotation - a performa invoice. There were no terms mentioned other than the price - even which I had asked them to revise and send. That didn't happen. I told them that the revised price should be 35500 and the owner Mr. Sabari, agreed to it. He asked me to pay 50% before shipping it. I sent him 17750 rupees to their sister concern upon his request - Manchester Food Products private limited. I specifically asked him to let me know BEFORE shipping it and that I will confirm if they can ship it via Parveen travels bus (which we had to travel 20 kms to go and get the machine from - which wasn't feasible for us unless the machine was placeable in our vehicle - tvs xl) or if they should wait until they send out bulk shipment. They shipped it to Parveen travels Coimbatore office without getting confirmation from me. I wasn't given a proper demo or photo of the finished product. We were in a tight spot around that time financially - so I decided to ask them to take the machine back, asking for our money back, cancelling. After 3 days and 200-300 calls of pleading, requesting, begging and whatnot - they returned 15000 rupees only saying they'll withhold 2750. Sabari asked me to talk to Karthikeyan (partner) and finalize the cancellation process. Karthikeyan agreed that they will refund the entire money on or before Jan 30th, 2018 (after selling the machine if before Jan 30th, and on Jan 30th, irrespective of sale). Now, when i contact them, they said that they won't return the money and will take that 2750 as cancellation charges(close to 20%) - of which 500 is transportation charge. No cancellation terms were disclosed before and now they are saying they won't return our money. Any legal guidance would be very helpful.