You can cancel a monthly or yearly Suzu subscription at any time, without giving a reason and without a notice period. You are not charged again, and Suzu keeps working until the end of the period you already paid for.
The link to manage your subscription in your purchase email takes you to the same place.
Write to suzu.support@proton.me with the email address you bought with and, if you have it, your order number. We cancel it and confirm by email. Please write at least two days before the renewal date so we can stop the next payment in time.
A lifetime licence is a one-time payment and never renews, so there is nothing to cancel.
Purchases are not refunded, including the unused part of a subscription period; see the terms.