Please contact us to stop renewals for you. This is the easiest way to turn off auto-renewals. Please be sure that there are no typos in your email address so that we can find your account.
If you bought using PayPal, you can cancel renewals from your PayPal account. PayPal has instructions at: https://www.paypal.com/selfhelp/article/FAQ2058
If you purchased a subscription directly and didn't use PayPal then you received a receipt email from SendOwl which contains a link to Manage Subscriptions. Search for this email with the term SendOwl and then click on the link to manage your subscription.
It may ask you to claim the account first or, if you have used the link before, it will ask you for your email and password. If you have forgotten your password you can click on the button to have it sent to you.
Or, simply contact us to stop auto-renewals for you.