1) Log in to your account on Pornbox.
2) Navigate to the member's area. (Top right corner, click on your username and bring out the drop down menu)
3) Locate the expiry date of your membership; it is displayed in the top right corner of the screen, under your username, once you click on it.
4) Click on the expiry date.
By following these steps, you will be directed to the cancellation process, which you can complete to cancel your membership.
Link to your subscription information is also :
https://pornbox.com/application/member/subscription