JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
I believe as the merchant, you will be able to cancel your buyers' subscription directly. Here's a guide from the Paypal support: https://support.google.com/payments/merchant/answer/3094698?hl=en
Your users will also be able to cancel the subscription directly in their Paypal account as mentioned here: https://www.paypal.com/ph/webapps/helpcenter/helphub/article/?solutionId=FAQ577&topicID=CANCEL_A_PAYMENT_CA&m=TCI
To learn more about how to setup a recurring payment on JotForm, you can follow this guide: http://www.jotform.com/help/166-How-to-setup-a-recurring-payment-option
I hope that helps.