A method may include receiving an online purchase request in a merchant interface from an electronic device of a customer. The online purchase request includes payment related information of payment card associated with customer for purchasing an item at a set price. Method includes sending an OTP request to payment server. Method further includes receiving an OTP from payment server, and storing OTP as a merchant OTP. Further, method includes facilitating sending OTP to registered contact identifier of customer. Further, method includes providing an option to customer to input a customer OTP in merchant interface. Thereafter, upon receipt of customer OTP from customer, the method includes locking an online purchase order of item for the set price based on one or more conditions. Payment transaction from payment card is actuated after a time period of locking the online purchase order based on the one or more conditions.