'Activation Lock for iPhone, iPad, and iPod touch' is a security feature that's designed to prevent anyone else from using an iPhone, iPad, or iPod touch, if it's ever lost or stolen. To learn more click here --> http://support.apple.com/HT201365
For an individual to remove an activation lock absolutely requires the information for the account that applied the lock. Click on this link to learn 'How to remove Activation Lock' --> https://support.apple.com/HT201441
Get the previous owner to try this:
iCloud: Remove your device from Find My iPhone
https://support.apple.com/guide/icloud/remove-a-device-mmfc0eeddd/icloud
• "If you forgot to turn off Find My [device] before you sold or gave away your iPhone, iPad, iPod touch, Mac, or Apple Watch, you can turn off Activation Lock using Find My iPhone on iCloud.com. "
What to do before selling or giving away your iPhone, iPad, or iPod touch "Use these steps to remove your personal information from a device, even if you don't have it anymore." Click here --> https://support.apple.com/HT201351
If necessary and you are willing to wait, Apple can completely reset a device if a person can provide sufficient evidence of valid ownership. Get the previous owner to do this online at: Activation Lock support request - https://al-support.apple.com/#/additional-support Apple says, "Proof of ownership documentation is required," but does not state what currently constitutes proof. Prior to this new online service Apple typically required the original receipt issued by Apple or an Apple Authorized Reseller and documented provenance (so typically it would be the original owner who does this).
If you cannot remove the lock the device is useless to you. Ask for a refund.
