you see the 40,00 and the 200,00 right? a comma is the same as a . for you so 40.00=40,00.
To get the Subtotal you need to add the 200 and 40 together which is not 280.
Verzendkosten translates to shipment costs and Korting translates to discount. Totaalbedrag should be the total amount that this order costs.
Do I need to explain why 2800 is the wrong number or do you understand it?