Follow these steps and questions: 

1. Determine the platform and the campaign? (Indiegogo, Kickstarter / Hot Pocket, Ember)
2. Find the person's name in the Crowdfunding Discount Codes Google Sheet (Linked In Column E ->). 
3. Is there a Discount Code created for that individual?
4. If there is NO code - Mark the row Red and Move to the Refund Section of the sheet. Then, proceed to make the refund on the platform.
5. If there is a code - Copy the code and use it to search Shopify orders for this discount code (* Use the right Shopify store).
6. If the Code has been used, go back to the Crowdfunding Discounts Sheet and mark the row Red, and drag it to the bottom of the sheet.
7. Now, go back to the Shopify order and make sure you are very clear on what products you are refunded for the customer. For example, suppose the customer ordered additional products that payment information is stored in Shopify while the Kickstarter or Indiegogo order amount is stored in Kickstarter or Indiegogo. Once determined what items to refund, issue a refund on the correct Platform and Shopify Store, if making edits, follows the standard procedure with editing a Shopify order. Be sure to remind the backer that issuing this refund forfeits their Kickstarter Backer pricing will not be available in the future.
8. If the code has NOT been used. Go to the "Bulk Discount App" in Shopify and locate the code, then deactivate the code, mark the row red and drag to the refund section in the Crowdfunding Discounts Sheet, and then make the refund on the appropriate platform.

Video reference: