How should I structure my refund policy?

I have a simple SaaS with a free trial set up with Stripe. My SaaS can be used both for b2b and b2c. I want customers to be happy, and providing refunds even with a free trial can be a great way to get feedback.

HOWEVER, refunds aren't free for me! Stripe clearly says the processing fee will not be returned to me, and sometimes a refund might incur additional fees. So I am guaranteed to lose money for every refund.

That makes me hesitant to provide a generous refund policy. So how should I phrase my refund policy?

"Absolutely no refunds"
"Generally no refunds"
"7-day refund"
"14-day refund"