My brother borrowed ₹2.5 Lakhs from his friend and asked me to be the guarantor. I gave the lender a blank cheque and a signed stamp paper as security. But the loan transaction never happened, and now my brother is missing. His friend is demanding I repay the loan, threatening legal action. What should I do?

You are legally obligated to repay the loan since you provided a blank cheque and signed stamp paper as security, even if the loan was never disbursed. You should immediately consult a lawyer to understand your legal options and potential defenses, such as proving the loan was never actually given to your brother.