Windy is a great app. I had a subscription to support it, even though I'm not really using premium features.
The problem is fastspring, which had me spamming with emails, plus re-newing subsciption was way harder than it should be.
I know fastspring from the other side, (they service payments for Adobe Community Exchange), so I know they're equally useless on the payment collector side too.
That's why I cancelled. Just wanted you to know. Please try to find a better payment provider for desktop.
P.S. Also having non-recurring subscription option would be nice.