Buyer is asking for compensation when we don't want to sell our house

We initially wanted to sell our house, a buyer contacted us. The deal was for 50 lacs. We were okay with it. They gave us a token advance of 10000 rupees in cash. Then few days later, when we realized that there can be an increase in the UDS of our property and we didn't want to sell it anymore. So, we returned the entire token advance via UPI transaction. The buyer initally planned to buy our house partially from a bank loan and rest of the amount by themselves. A guy from the bank visited our house for evaluation and even bank manager came once and took a photo. Now, since we don't want to sell our house, the buyer is asking compensation for the amount he had spent for bank evaluation and legal fees, that is, 15000 rupees. We are even ready to pay half of it, that is, 7500 rupees. But now, the buyer is saying they got a loan from loan shark of 15 lakhs and wants us to compensate for it. They indirectly want to force us to sell the property. No kind of any agreement has been signed till now. They are telling they'll visit home with an advocate to talk further. What points can they bring up through the advocate and how should we safeguard us? Please help, sir.