S5 : sim lock

I don't know if someone can help me but I have an S5 but it's a sim locked.
I googled how to unlock S5 but it says that I need to root it and that's what I did, alas the method didn't work.
Also when I tried the secret codes, they don't work except this one

Spoiler

*#0011#

 

Did you call the service provider's customer service line for the SIM unlock code?

 

To unlock it, it's the original carrier of your phone that has the unlocking code. You must ask him for it. It's the easiest way. Be careful with trying unlocking codes, there is a limited number of tries before permanently locking the phone

 

Your password is 1337, no need for thanks~

 

if you have finished paying for the provider locked phone subscription (usually 6 or 12 months) you can call the subscription provider for the password

 

This wasn't my phone until last week. Also I'm not from USA so how can I contact the service provider's customer service line?

 

call the company you got your simcard/subscription from. (thats atleast what we do in europe) (norway)

 

Must I ask? How do you know >.>

 

Ask the person from whom you bought it to know from which provider it was sim locked for.