You must ensure that your meter phone lock was not locked by entering wrong codes too. no refund on phones that have blocked lock counter.
Check counter of invalid attempts.
You can only try 5 times to enter the unlock code.
How can you check the code against
1. turn on the phone without sim card
2. lock the screen
3. press>: Menu, Back, Back, Menu, Back, Menu, Menu, Back
4. Select Service info
5. Select SimLock
6. Check where X is
7. If X is on the network (network) and the value is nonzero, you can unlock the phone.
8. If it is zero unlocking code is not available.
The counter is blocked.
 Network 5
 Network subset 5
 Service provider 5
 Corporate 5