Fraud on my Apple cash card

If it has not yet bean accepted you may be able to cancel it. Otherwise, it's like any other private transaction between two people. It is not protected, and it's up to you to verify the validity of the person you are sending money to. It's no different than handing money to a guy on a street corner.

click here ➜ If you sent a payment from Apple Cash and want to cancel it- Apple Support

You might be able to cancel it, but I’d expect that money is already gone.

How to cancel, if still pending:

If you have an issue with an Apple Cash transaction - Apple Support

As Apple Cash works like cash, again, the money may well be gone.