Default sim unlock only on 2.3.3

I Have tried everythong i want to install kit kat but evrytime i do anything past 2.3.3 i cannot unlock sim for some reason i even tried that i unlocked it then updated trough kies and once again still canot unlock pls help anyone its been 5 days of me trying this i9100m I want to use this phone but i dont want to be on gingerbread 2.3.3