How do i report a stolen card or potential fraud

To report a lost or stolen card, see the following from Lock or unlock Apple Card - Apple Support

If your titanium Apple Card is lost or stolen

First, lock your titanium Apple Card. Then use your iPhone or iPad to request a replacement card.

If your iPhone and titanium Apple Card are both missing or stolen:

1. Call Goldman Sachs for a replacement Apple Card at (877) 255-5923.
2. Then locate your missing iPhone with Find My and protect your information.

If you only need to dispute a charge, see information in Dispute a charge to your Apple Card - Apple Support