Отвязать ios от apple id
I fell for the scammers' trick, at their request I went to their Apple ID, they changed the password and threatened to block the phone. I have the receipt, the box and the iPhone itself
iPhone 11
I'm not quite sure what you were tricked into doing, but see:
If you think your Apple Account has been compromised - Apple Support
If you can get back into your Apple Account, you should then be able to release any lock on your iPhone.
If you mean that you signed into a scammer's Apple ID on your iPhone and they've now locked it or are threatening to do so, then there may be nothing you can do, but you can try the "Start a support request" process listed in this Apple support article:
How to remove Activation Lock - Apple Support
Regards.