Please help, 我有一箱衣服和四個小箱子的貨現在正在海關，

所有物品value寫的是４００美金。　今天接到電話和兩張表格，要我填好發過去，怎麽還要我的social security card copy呢？海關到底要幹啥啊，不就一箱衣服和四小箱的貨嗎。

這是收到的信：
The parcel your sister send is held up in customs. In order to clear and deliver the shipment we need the following:



1. A clear copy of your social security card back and front.
2. Complete the Footwear Detail Sheet form attached.
3. Look at the invoice attached and write what is the unit value then the total values.
4. Write what is the fabric content for all the garments e.g cotton, polyester etc.
5. Write what the jewelry is made of. Eg. Plastic or metal.