How can I unlock my Nokia Lumia 2520?

[Windows Central Question]

Unlocking of Nokia Lumia 2520

I bought Lumia 2520 ATT tablet on ebay and when I received it in Ghana, Africa it was locked to ATT. I managed to get the unlock code from ATT but when I launch the ATT allaccess app, there is no place to enter the unlock code. Their service is not available in Ghana so how can I use the solution provided earlier. I need help?

 

[Visa Declined]

Re: Unlocking of Nokia Lumia 2520

When you put a non-AT&T sim card in the tablet and turn it on, does it not ask you to enter a code?