Most mobile devices are network locked by the mobile network companies. This is done to prevent access to other networks different from their own. In cases like this, you may want to move to cheaper rates network, in order to use other network carriers with this phone, it has to be unlocked.
This is a huge task!
Some people give the impression that they are able to handle tasks like this when they barely understand what they are doing. That may lead to blocking the phone or lock you forever with the original network the phone locked to.
It is really important that you go to a professional for your phone to be unlocked. An unlocked phone grants you access to use a different SIM from any affordable network of your choice.
If you have a locked phone, you can bring it to us for unlocking; we deal with all makes and models of phones and will unlock your phone for you. If you have any need to leave the UK, you will be able to use any SIM card of your choice with the same phone. This is a great offer because you will not be incurring hefty roaming charges unlike when your phone is locked and you have to use the same SIM no matter the country.