There are total two ways for handling the refund request.
1- Earn Points
Product Assigned Points: When user make a refund request of that product which have some of the assigned points then after refunding the amount, the earned points will be deducted from his/her account.
Per $ Spent Point: When user make a refund request for an order from which he/she earned some of the points, then after refunding the amount, earned points will be deducted from his/her account.
Product Purchase through Points: When customer makes any refund request for that product which has been purchased free of cost(by using his/her points) then after refund request, deducted points will be refunded to his/her account.