You may cancel your membership at anytime. You can visit the website of the billing partner to cancel your membership yourself.
If you are unsure which of these companies billed you, please check the subscription receipt that you received when joined.
If you joined through Paypal/Epoch, your cancellation form is here:
On that page you can cancel by filling out any 2 fields of the 4 fields.
After cancellation your user credentials will stay active for the remainder of your subscription.