Make sure the first charge was not a hold. This is what happens if you check into a hotel with a debit card.
You should be charged the day and time the product was shipped, not when you ordered it.
Perhaps there is a screw-up at Amazon, putting a hold but not taking it off as the package was shipped.
NEVER, NEVER, NEVER,
NEVER, NEVER, NEVER,
NEVER, NEVER, NEVER
use a debit card.
NEVER, NEVER, NEVER,
NEVER, NEVER, NEVER,
NEVER, NEVER, NEVER
have a debit card.