Thanks for your questions. you can unlock your Samsung SGH T599N from YEMEN  by using this software  Octopus Box Samsung software version 1.4.6. 

If you use this tools, then you need to following steps-

Welcome to Octoplus/Octopus Box Samsung software version 1.4.6

To connect SGH-T599N phone you have to perform the following steps:
1. Disconnect USB cable from phone.
2. Go to Menu->Settings->Applications->Development.
3. Turn on “USB Debugging” option.
4. When message is appear press “Yes”.
5. Go to dial window.
6. Enter “*#7284#” number.
7. Set “UART” radio button to “Modem” value.
7. Set “USB” radio button to “PDA” value.
8. Restart phone.
9. Press “Read Info” in software.
————————————–
Platform: Samsung Android
Selected port: COM4
Selected model: SGH-T599N
Searching for a phone. Please wait…
Phone found.
ADB server killed.
Firmware compiled date: Fri Apr 12 02:23:38 KST 2013
PDA version: T599NUVAMD4
CSC version: T599NTMBAMD4
SW version: T599NUVAMD4
Phone IMEI: 35643305*******
Phone SN: R21D8BERV2W
Android version: 4.1.2 (JZO54K)
Unlocking phone…
Reading data from phone…
Data read successfully.
Please conect phone to BOX via UART cable.
Searching for a phone. Please wait…
Phone found.
Unlocking phone. This can take some time. Please wait…
Please insert card into phone, if phone is locked, then type 00000000
Phone is successfully unlocked
——————————————–

If you buy this software, then you could unlock all Samsung and LG mobile phone.

Product description
Octopus Box is a professional device for LG cell phone service. It can be used to unlock, flash and recover LG phones, resolve freeze problems and restore IMEI, NVM, camera and network.

Octopus Box Features
•Complete A2 platform support
•Advanced language pack editor
•Wide flash support
•Complete Softbank support
•Free real-time online updates
•Richest and constantly updatable flash files database at Boot-Loader V2.0

Main Features:
•Direct unlock
•All locks reset
•Read phone information
•Firmware update
•Read/write full flash and calibration data files
•Read firmware version
•Full factory reset

You can buy this product from here.

I suggest you can approach Superunlockcodes.com and specify the country,locked network of Samsung T599 .Based on the availability you can get the permanent unlock service along with free instructions.