You can return the order price to their Store Credit Accounts. In this way, Customers are more likely to come back and use Store Credit's to buy some other items in your store.

You can see Magento 2 Credit memo dashboard like the screenshot attached below: Info macro

Now, How to Create Magento 2 Credit Memo-

Step 1: Go to admin sidebar, click on Sales and then choose Orders to see all of your current orders.

Step 2: Choose a completed or Processing order in the table in Order management view and click View in the Action column to see all detail information of that order.

Step 3: Now click Credit Memo, but remember Credit Memo will only appear if the order is invoiced.

Now to Return the amount via store credit do the following-

Go to Credit Memo, Scroll down, Check Refund via Credit Score and Click Refund Offline.

Info macro

It's Fast, easy, brilliant! Satisfied customer may use credits to pay for the next purchase.