We should be flooding their customer support team with complaints about this issue. When they inevitably say they can't help you other than to pass along your feedback, let them know you'll be leaving negative feedback on the customer service experience.
Additionally, you can email the CEO directly to let him know this is unacceptable:email@example.com
Consider including the following:
1. If this is an unavoidable change in Stripe's terms, you should find a new merchant provider or banking partner that doesn't charge these return fees.
2. If this is not resolved soon, I will be moving my online business to Squarespace where they do return fees on refunds.