You can cancel your subscription anytime in the "Subscriptions" section of your My Account area. Note that you will no longer be able to use MapifyPro if this is canceled.
This is accessible from https://mapifypro.com/my-account.
Add-ons do not require a subscription and are yours to keep after a single purchase.
You may also submit a ticket here in our support system if you would like us to cancel the subscription for you.