On the basis that unlocking a mobile phone is illegaland that the process is different for each mobile phone model, I bring you here a compilation of links where you will be able to unlock your phone in many different ways:
-Trycktill, Unlock by IMEI for free, where you put the brand, the model of your phone and the IMEI code, then they give you the code to unlock it for free.
-LiberarPorIMEI.com, Another website to unlock by IMEI method for free.
-Nokia free, is a website specialised in unlocking nokia phones, easy and free.
–MOVICAL.NETThey unlock almost all mobile phones on the market, both by code and by cable.
-BAZARSUR, Web to unlock by IMEI the most complicated phones, it is not free.
–GrupoGSMA website that has manuals on how to unlock many phone models as well as material on how to do it, they also unlock phones by IMEI.
-FreeGSMs, here they sell cables and tools to unlock mobile phones (unlock material). They also unlock phones by IMEI.
-Moviltuning, lots of information on how to unlock your mobile phone, repairs, codes and more.
I hope you find these links useful, and if you know more, just let me know.