What does it mean if it shows "You have a gift" and how do I review amount in my Apple Account?

Did you receive an email as seen when a Gift is sent to you here:

After the gift is sent, the recipient gets an email. When they open the email and click Redeem, the item automatically downloads to their device.

Gift apps, media, and more from Apple - Apple Support

Or is there something else you saw?

Still have no idea what you saw. If money was sent to you and you did not receive it in 7 days, it would have been returned to the sender.

Send and receive money with Apple Cash - Apple Support