According to https://www.paypal.com/dm/selfhelp/article/how-do-i-cancel-a-recurring-payment,-subscription,-or-automatic-billing-agreement-i-have-with-a-merchant-faq1067, you have to follow these steps:
- Log in to your PayPal account.
- Click Profile (the gear icon) on the top right corner of the page.
- Click Pre-approved payments under “Payment settings”.
- Select the merchant whose agreement you want to cancel, and click Cancel.
- Follow the instructions to cancel the agreement.