My device Is newly purchased online trade swapped phones and cash and done. Text messages to verify both coherence,knowledge & legality

And? 

The fact that you have proof positive that you bought the phone doesn’t means that it can’t be a lost or stolen phone.  The person who you bought it from could be a thief, or have found the phone, and sold it. The phone is blacklisted and it’s going to stay blacklisted unless the person who added it to the blacklist asks to have it removed.  Since that person isn’t you, there is nothing you can do to change it.  Get your money back from the seller, if you can.

Huh? 

English teachers everywhere felt the disturbance in the force.  🤦🏼‍♀️

Try writing a heading sentence, then details which explain your phone purchase.  Like where and from whom purchased?