You can cancel your subscription from your Paypal transaction history.

A subscription can be canceled up to the day of the next scheduled payment.

Here's How:

1. Log in to your PayPal account.
2. Click History at the top of the page.
3. Select Subscriptions from the Show menu.
4. Check the From box and change the date back 2 years.
5. Click Search.
6. Click Details to view the details of a specific Subscription Creation.
7. Click Cancel Subscription.
8. Click Cancel Subscription again.