Activation

Hello ~ That is the activation lock. If the person/persons that you bought the iPhone from cannot or will not remove it …the iPhone is basically useless to you. If they cannot/will not remove it…return it and get your money back. We cannot help remove it nor can Apple. The receipt that is shown will not be proof enough for Apple to assist. Take a look here by clicking on the links below

Activation Lock for iPhone, iPad, and iPod touch - Apple Support

Also:

The All Too Common SAD Reality of Buying a Used iPad/iPhone

~Katana-San~

Unless you can get the original owner to remove their Apple ID from this iPhone, it will be useless to you as you will not be able to remove activation lock ... which is a theft prevention method.

If you cannot get a hold of the owner, I strongly suggest that you return this phone to the seller for a full refund.

Unfortunately the last owner is the only one who can erase the phone by using their credentials. If you are unable to contact him your phone will not work.