Samsung i9500 Galaxy S4 16GB Unlocked Black Mist "barring code" Questions

samsung galaxsy s4 imei code under the battery, in a sticker.. above the bar code

...code at low cost and unlock your SAMSUNG phone. I've got a samsung GALAXY Nexus GT-I9250 and Telstra said that the previous owners have put a lock/barring on phone I need to remove this can u help? ...