If you have bought your mobile directly from a mobile provider, it will only work with one of their SIM cards.
To check whether your Phone is locked or not, follow the steps mentioned below:
-Insert your BT mobile sim into your phone.
-If you are unable to see “BT” symbol somewhere on the screen, it means your phone is locked.
-You might also get the message “SIM not valid”.
To unlock your phone, you have to contact your previous mobile provider. They will assist you in unlocking the phone either by unlocking it for you or providing the unlock code.
If you are contacting your previous mobile provider, provide the following information:
-Your phone number
-Account number
-The make and model of your mobile phone.
-Your mobile phone IMEI number. If you don’t know your phone IMEI number, dial “ *#06# “ on your phone.
If the problem still persists, contact BT Customer Service here http://www.qwiknumbers.com/bt-customer-services.
sophia, May 2016