The coupon will lose its value and cannot be replaced when refunding a product.
Any returning online order that goes below the coupon minimum spend, the discount will be voided and deducted from the product value.
Please refer to the below examples as your references:
Scenario A: Order value above the coupon minimum spend.
Order Value (before coupon discount applied): $100
Coupon Used: Off $5, minimum spend $60
Price of the returned product: $30
Remaining Order Value (after returned): $70
Total Refund Amount: $30
Scenario B: Order value below the coupon minimum spend.
Order Value (before coupon discount applied): $100
Coupon Used: Off $5, minimum spend $60
Price of the returned product: $55
Remaining Order Value (after returned): $45
Total Refund Amount: ($55 - $5) = $50