Activation lock to owner

Contact the previous owner, and ask them to complete the steps outlined in What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch.

Try get your money back, if the seller is not helping.

Activation Lock is a theft deterrent feature with no bypass or workaround.

Without the owner's authorisation (Apple ID & password), no thief or anyone including you can re-use the device.

You can recycle the device responsibly.