今天早上打電話到CBP谘詢過境的一些問題， 被索要個人信息， 問題大嗎？

情況是這樣， 本人和老公都是加國護照， 兩個小孩持有美國護照和加國楓葉卡。
今天早上我打電話到peace bridge 的CBP詢問過境消息， 對方問我last name,first name, date of birth,
我講了我的出生月份後， 就問："do I  have to tell you this? I just inquiring information。“
對方回答：“if you don't tell me , I cannot help you.
我說: " I am still in Toronto, and I am not crossing board. I don't feel comfortable to give me personal
information through telephone."
對方說：” you even don't want to tell me your birthday, I can't help you. Have a nice day!"

不明白US CBP 目的何在？