質問させてください。
amazon.comで注文したところ以下のようなメールが届きました。

Hello,

We're writing to let you know we processed your refund of $29.63 for your Order ○○○○○○ from Japan shop SY: We can ship to outside USA (Europe, Asia, Oceania, Africa, etc.)..

This refund is for the following item(s):

Item: ○○○○○○
Quantity: 1
ASIN: ○○○○○○
Reason for refund: Account adjustment

Here's the breakdown of your refund for this item:

Item Refund: $20.64
Shipping Refund: $8.99

We'll apply your refund to the following payment method(s):

Visa Credit Card: $29.63

We've processed a refund for the above order in the amount of $29.63.
In most cases, once a refund has been submitted, the issuing bank will post it to your account within 3-5 business days when issued to a credit card.
Refunds issued to a bank account or pin-less debit typically take 10 business days to reflect on the account balance.
This time frame may vary from one financial institution to another.

おそらく注文がキャンセルされたと思うのですが、返金理由にあるAccount adjustment(アカウント調整)とはどういうことなのでしょうか？