If visa/mc/amex are so much better, people can use them.
Stripe uses visa/mc/amex, it is not a competitor. You completely missed my point. Stripe uses visa/mc/amex to process credit card transactions, then when a refund is issued the CC companies return the charged amount to Stripe, but Stripe does not return the full amount back to the customer. They keep a percentage. This is what I consider "borderline fraudulent".
Charging a flat fee for a service doesn't seem that fraudulent to me.
But it is not a flat fee. They keep a percentage of the refunded amount. So if a customer bought a $1000 item, then changed their mind and cancelled the order 5 min later, Stripe would still keep $40 just for the fun of it. A small flat fee to cover network expenses would be more appropriate, not a percentage of the amount.