If it is network locked (only works on one network), then you need to purchase an unlock code from sim-lock.net for 6.99 Euros (about R80). You will find instructions on how to input the code once bought from the same webpage above. The above method is ideal if you are still obligated to the carrier that subsidised the phone (the carrier or service provider that the phone is currently locked to) - e.g.would be if the phone was taken on contract for a specifict period which has not elapsed for now. If you are no longer obligigated in such manner, you can simply contact the current carrier's Customer Care and ask for the unlock code. Please do comment under this self same question if it is not a network unlock assistance you needed.