That would depend on the PayPal product used behind the scene, Website Payment Standard or Website Payment Pro and the seller. With WP Standard, if you cancel, all PayPal does is ensure that you are not billed for the next month. With WP Pro, the seller controls the entire Subscription cycle via the seller's web site. Regardless of which PayPal product is used, it would be up to seller to offer or initiate a refund, not PayPal.. It's also the responsibility of the seller to have a clear policy on their web site explaining their cancellation and/or refund policy.