You can follow these instructions to cancel any recurring payment profiles in PayPal:
https://www.paypal.com/uk/webapps/helpcenter/helphub/article/?articleID=FAQ2145&m=SRE
The cancel link only works for Stripe subscriptions at present, IIRC. The reason for this is that we have not yet been granted PayPal Pro services, which would allow us to remotely cancel payment profiles in PayPal.