In layman's terms, a chargeback, also known as a "friendly dispute", is raised by the cardholder (end-user) against a specific transaction and reported to their card issuing bank.
A chargeback is a feature offered by banks and card networks like Visa and MasterCard to protect purchasers from illegal or fraudulent payments.
When a cardholder files a complaint, the bank reports it to Razorpay and investigates.