I guess you have it set to take from a paypal account ?
I have just checked on my paypal,
If you go to the latest payment (as its a pre-approved payment) you can click on it to expand the details then click on "Manage Overland Bound Payments"
The next screen should show you your subscription details and at the bottom is where the payment method that paypal would take it from
Outside of paypal I would be unsure - best to contact OB HQ on
info@overlandbound.com