Q: About I cloud

Hello Everyone

My name is zeeshan from pakistan 1 months ago i brought i phone 6 from OLX and recently i had installed new version of ios when i installed and restore my device ill get stuck to activating my i phone because there is i cloud and its old user id on this phone ill contact Him But his Phone Is powered Off And there Is no Address Of him So Tell Me There Is any solution to bypass I cloud.

Its Highly Appreciate If I get help From Anyone Thank You Very Much.