how to unlock mobile when i don't know ?

Which phone you are using currently? If it is an iPhone, get lock -info service from the online service provider Mobileunlocksolutions.com and get Remote unlocking method from them to unlock your phone . If your phone is other than iPhone, you need to know your network (locked network) . After that, you can get unlock code from the above mentioned provider and unlock your phone.

sarva
June 2013