After a monthly donation is made, the donor will get an email to setup his Donorbox donor account.
If you didn't setup your account via the setup email please use the "Retrieve My Account" link. This will let you establish a donor account.
You will then have access to your monthly donation plans. Click the edit button to the right of the donation plan you wish to cancel (see image below).
Then, click the red cancel button below your donation plan summary. That's it!
Canceling PayPal Recurring Donations
Paypal recurring donations are managed on the donor's PayPal account. For the most up-to-date info on how to cancel PayPal donation please go to https://www.paypal.com/us/selfhelp/article/How-do-I-cancel-an-automatic-payment-I-have-with-a-merchant-FAQ2058