Since July 1st, 2019 Akeeba Ltd does not sell products directly to end users. All sales are performed through our authorized reseller, Paddle.
Paddle handles billing and invoicing. They are responsible for figuring out sales tax applicability and amount, take your money and issue the corresponding invoice for your order.
Akeeba Ltd only fulfills the order. This means that we only provide software downloads and support. We do not handle billing or invoicing. As a result we cannot help you with billing or invoicing issues.
I only have limited access to help you. Namely, the vendor backend at Paddle which shows complete transactions. Luckily, I was able to help you. It looks like you purchased two separate subscriptions, 46 seconds apart. This means that you did not, in fact, receive two copies of each email from PayPal and Paddle. They were two different sets with a different subscription ID and a different PayPal transaction ID. This is very different than being billed twice for the same subscription (Paddle should have caught it) or transaction (PayPal should have caught it).
I assume that you either accidentally clicked the subscribe button twice or something went wrong with your browser. However, since the payment overlay and the entire payment process is handled by Paddle and I don't have access to these third party systems I cannot tell you what happened. If you need to know please contact firstname.lastname@example.org and ask them to help you understand why transaction 10679484-7428109 was followed by 10679507-7428127 a mere 46 seconds later. They should be able to answer it.
All I could from my end is refund the first transaction (10679484-7428109) and cancel the erroneous double subscription. You should see your money back in your PayPal account in the next 2-10 days.
Nicholas K. Dionysopoulos
Lead Developer and Director