The iPhone is blocked on the fraudster's Apple ID

The IMEI/Serial number must be on the original receipt where it shows YOU purchased it, but you cannot remove the Activation Lock with an IMEI number alone, or even with the box.

https://al-support.apple.com/#/additional-support

• Proof of ownership documentation is required.
• Proof of ownership must include the product serial number, IMEI or MEID
• Your device must not be in Lost Mode.

Feel free to submit your request and see what Apple says.

You will not be able to remove the Activation lock without the original receipt from Apple or Authorized Apple Seller. The box is not proof of anything. It is a tough lesson to learn, but you should NEVER add someone else's Apple Account to your device.

Helps right now