We support refunds for Tamara orders from OpenCart, with the Refund option on our partners portal: [Ref.Refunding orders - Partner's Portal]
Search for the respective order either by the order reference shared from your end or the order reference generated from Tamara end > Click on the order, once it shows up on the Orders table.
On clicking, you will be redirected to the order details page where more information about the order will be available.
At the bottom of the page, next to order items:
Click on ‘Refund’ > Enter the amount you need to refund to the customer.