That’s the problem with buying used items that can be permanently locked. There is even a good change the product was stolen. The numerous Apple Accounts are from people buying the item, discovering it’s locked and selling it again. Personally, I’d go to my local police and turn the item in and explain the circumstances.
Apple will review requests for assistance from local law enforcement.
If you’re in the US please call 1-800-MY-APPLE or outside the US, consult the support articles below.
Contact Apple for support and service - Apple Support
Genius Bar Reservation and Apple Support Options - Apple
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Live Chat with an Apple Advisor in Messages.