I ordered some Amazon cards to burn my points before Christmas. When only one of the cards arrived, I logged back on the see what the website said and the other cards had been put on backorder but nothing had been emailed. I cancelled those cards, had to wait for the points to redeposit and then ordered in different denominations. Second batch was delivered a couple of weeks later.

My advice would be to leave plenty of time for the order and to check the order every couple of days to keep on top of order status.