Hi Leslie,
Thank you for reaching out to the community forums to share your experience with transaction fees and refunds on your store as well.
I recognize your frustration if you were not aware of this policy before refunding this transaction. The terms of use for Shopify Payments does include this information and it is also inline with other major online payment processors. This policy was introduced at the beginning of 2020 for all merchants located in the USA.
Shopify payments is an optional payment gateway and you have the ability to choose an alternate gateway that better suits your business and your needs. You also have the ability to refund a customer less processing fees at any time. When processing a refund you can change the refund amount to reflect that before processing.
You can read more about this policy for Shopify, PayPal and Stripe using the links below:
Paypal - Refund Payments for Individual Transactions
Understanding fees for refunded payments : Stripe: Support
Shopify Payments Terms of Service - Canada - Shopify
The decision to move forward with any form of legal action is entirely yours to make. If you wish to connect with our legal team you can email them at legal@shopify.com at any time and they can further assist with your concerns.