how to block my device if its stolen and lost mode and find my iphone is off

Ask your wireless carrier to blacklist it. Without Find My, no other methods exist.

(261743)

With Find My turned off, even if your carrier blacklists the phone, the thief will be able to reset it and use it as an "iPod touch".

The phone will still be able to connect to Wi-Fi Internet service, play music, run apps, etc. It just won't be able to make or receive cellular phone calls, send or receive SMS/MMS/RCS messages, or use cellular data.

Saegzz wrote:

I don’t understand how any of this happened if you wiped your device first.

If the OP prepared the phone for a new owner, as outlined in

What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support

that would have removed the phone's association with the OP's Apple Account.

The phone would start up to the "Hello" screen, as if it were brand-new, out of the box. "Find My" would not be on, because the phone would not be associated with any Apple Account.

If I understand correctly, the problem is that the OP gave the scammer "buyer" physical possession of the reset phone before discovering that the payment that the scammer had made was fake. The scammer made off with the OP's phone, and the OP was left holding the bag, without the money the scammer had promised to pay, and had pretended to pay, in a fraudulent manner. The scammer probably then "disappeared" (as scammers like to do). The OP wants to "brick" the phone, but because Find My was turned off, only partial "bricking" (i.e., carrier blacklisting) is possible.

Hello~ Click on below and review…

If your iPhone or iPad was stolen - Apple Support

Contact your carrier.

~Katana-San~

yalraz wrote:

i told him my account no

I would suggest monitoring your bank account very carefully for the next few months.

You might even want to go through the inconvenience of asking your bank to close out that account number and reopen your account under a different number (if they think it will do any good).

Why? I'm thinking that if the scammer has your bank account number, they might just try reaching into your bank account directly – not to pay you for the phone, but to steal more from you, by taking money out. But maybe I am being too paranoid …

I don’t understand how any of this happened if you wiped your device first.

btw I’m totally impressed you said all that without one comma or period