Device Unlock

Then you need to either call them or file a FCC complaint.

Some body drop request for this imei and check please 358371068679227

This is a customer forum not AT&T. No one here can do anything for you 

I try it from Russia

When I put that IMEI in the unlocking portal, I get the message that says that the device isn’t paid off yet, so it’s not going to be unlocked.  And before it comes up, AT&T won’t let you pay off any else’s phone because they won’t provide the needed account information, so it will never be unlocked, and given that it’s an iPhone 6, it’s probably been overdue for quite a while.