I had the exact same thing happen.
I placed an order (once) on 2-25-15, then today received notice about two cancelled orders due to no payment after 3 days. Logging into the portal also shows cancelled orders.
Paypal shows atlanticpaypalcs@digitalriver.com river received payment.
Cancellation orders reference "Order ID", portal shows a "Order Number" text input field, why is this? I don't want to "Assume" anything. Seems that this should be fixed.
My avast still shows my "subscription" (which it isn't since I don't auto renew) is good until March, 2016.
I hope this fixes itself because I am not going to do anything further, if I do have to waste more of my time, I will be disputing the charge with PP and going with another AV company.