As a web designer, i find this one a bit strange. If you look at the times of the orders there is only 3 minutes between them.
If you did the payment did you use a credit card, paypal or did your parents do it for you. Either way someone did not just press the button twice for the same order, they did 2 orders.
I suspect the server took the order and processed it but before your connection read the answer your system timed out, This often happens, so rather than check your account you "or they" did it again.
I am sure if you explain what happened in an email they will sort it, but without emailing details how are they to now you didnt want 2
Keep calm and ask