You can cancel your subscription at your convenience. To cancel, you must be logged into your Account Manager: https://theoilmoney.com/secure/member and click on the button: Payments History. Under the words Your Active Subscriptions you will find your current active subscription(s) with: Date, Invoice #, Product, etc. At the very end of that is the option to Cancel Subscription. Click on it and it will proceed to cancel the subscription.
Note: This will cancel the subscription and future payments. You will still be able to log into your Account Manger if you wish to return / order a different product. Simply remember and use the same login credentials.