Most items purchased from sellers listed on grocery mart are returnable within the return window, except those that are explicitly identified as not returnable.
For the products that are returned by the customer, the refund is issued to the original payment method (in case of pre-paid transactions) or to the bank account / as Amazon Pay balance (in case of Pay on Delivery orders), the details for making such refund and the timelines are detailed in the refund policy available here.