急急急？为什么在expedia订美国机票，总是不行，但每次都扣1美元，这是为什么？

用的中行万事达卡，不过到今年十月就到期了，试了两次，总是说：

We were unable to complete your booking at this time
You may wish to try again later. If your itinerary requires immediate action, please call our customer service center at 1-800-EXPEDIA (1-800-397-3342) or 1-404-728-8787.

Failed item:
Flight: Beijing -- Newark

Problem details:
Your request cannot be completed at this time. Please try again later.
If your itinerary requires immediate action, please call our customer service center at 1-800-EXPEDIA (1-800-397-3342) or 1-404-728-8787.

谁知道这是为什么吗？急急急，

另外这扣的1美元（两次就是2美元）是什么钱？