What can I do if I discover my identity was used to fraudulently take a loan?

File a police complaint immediately, reporting this as identity theft and fraud, and separately notify the lending institution in writing that you never applied for or authorised this loan, requesting they investigate and correct their records — don't delay, since this can affect your credit report and expose you to recovery action for a debt you never actually incurred.

Request your credit report from the credit bureaus to check whether this fraudulent loan has already been reported against you, and if so, formally dispute it, providing your police complaint and any other evidence supporting your claim that the loan was fraudulently taken in your name.

Most lenders have a specific fraud investigation process for exactly this kind of situation, and once satisfied it was genuinely fraudulent (not something you're falsely denying), they are generally expected to correct their records and not pursue you for repayment. Keep thorough records of every complaint and communication throughout this process, and consult a lawyer if the lender remains unresponsive or continues pursuing you despite your complaint.