Hi @Spire, welcome to our forum!
I can't provide any support for the actual code, but if you start the phone without a SIM card inserted > open up the phone application and type in *#*#7378423#*#* > Service info > SIM lock.
I assume it shows [X] Network x (x = a digit).
The digit will tell you how many unlocking attempts you have left and if this is at zero, there are no attempts left to enter the code. The code should be 16 digits long and it's only your operator that can provide this code for you, I won't be able to do that.
If it not at zero and the code doesn't work, get in touch with your operator/provider again and tell them that the code isn't working.
Let me know if that helps!
