Actually, refunds are free, but Stripe keeps the original fee for payment processing and covers it out of that. So you need to pay the transaction fee for the original purchase to make the customer whole. See https://support.stripe.com/questions/understanding-fees-for-....
In this case, since we know from the article that there are 474 charges, and a total of $73k processed, 474 * $0.30 + $73k * 0.029 comes out to $2,267 that the company owes Stripe
I think we paid around $2.7k in fees because of foreign cards. We also lost an additional $30k that month as we've refunded fully everyone including active customers that was bound to renew for real but another day.
In this case, since we know from the article that there are 474 charges, and a total of $73k processed, 474 * $0.30 + $73k * 0.029 comes out to $2,267 that the company owes Stripe