I have just been scammed selling my iphone

If you prepared the phone properly for sale, it won't be associated with your Apple ID, and so you won't be able to mark it as Lost to turn it into an Activation Locked "brick".

However, once you file a police report, you could submit a copy of it to your carrier (phone company). Your carrier might be willing to blacklist the phone, in which case no carrier who honors the blacklist would offer cellular voice, text message, or data service to the phone ever again.

If the phone stops working as a cellular phone, the buyer may file a complaint against you, so be prepared to show that you really were scammed, and that the buyer brought the blacklisting upon themselves.

Contact the police. There's really nothing anyone here or at Apple can do about it.

Contact the police. If the sale was through an online marketplace, contact them as well.

mervyn258 wrote:

I have been scammed by a buyer, stole my new iphone 16

That's a bummer. But what do you hope to accomplish here? We aren't the police. We aren't Apple. And Apple has nothing to do with you selling your iPhone. Sounds like a matter for the police.