I think you just go to your paypal account and remove it.
Edit - yes .. here it tells you: https://guildlaunch.uservoice.com/knowledgebase/articles/1045-how-do-i-cancel-my-subscription
I want to cancel my paypal subscription. How do I go about unlinking my paypal account so I am not charged?
If you created a subscription using the guest checkout in PayPal you will need to send an email to firstname.lastname@example.org requesting we cancel your subscription.
I emailed you guys last week about cancelling my subscription. I still have not got a reply back. Are you always this slow to respond to your customers?
I'm sorry I don't see an email from your address we have in our database. What email address did you send your request too? Please email support at email@example.com from the email address your Gamer Launch account is registered too. Once we receive the request, I can get you squared away.