Defrauded of more than $150 in Apple Gift Card

See the following excerpt from About Gift Card Scams - Apple Support and click on the blue contact link or call the phone number.

If you have additional questions, or if you believe you're the victim of a scam involving Apple gift cards, contact Apple Support online.

You can also call Apple at 800-275-2273 (U.S.) and say "gift cards" when prompted.

While it has not happened to me, I can say you are not alone. Specifically for Gift Cards, Apple has even published a support article to help users. Here in the US, it is a frequent topic usually around the holidays where the major news networks run stories alerting consumers of these types of scams.

About Gift Card Scams - Apple Support

Along with the common Gift Card scams, there are also phishing attempts through email/messages by people claiming to be someone they are not. They are specifically looking for your personal/financial information and may provide a link that opens a fake site where users provide their credentials, or a phone number to call and they will inadvertently give them their personal information.

Recognize and avoid social engineering schemes including phishing messages, phony support calls, and other scams - Apple Support