In the UNA -> Payment -> Settings -> Stripe
You ask for "Cancellation Email". But it is impossible to get an email address approved with a standard membership. When you try, you get the following error message: "Your current membership (Standard) doesn't allow you to 'Post links'."
All the best
Seems you need to add a system action "Post links" to this permission level via Studio->Permissions area.
It is in UNA.io => Settings -> Payments I can't add an email address, not on my own site.