Sgh-succ unlocking for 900mhz by code but
 

ok today i was try to unlocking SGH-T429 by this method
----------------------------------------------------------------------
First with different carrier SIM in phone at WRONG CARD screen ENTER on the keypad
*2767*3855# (wait 10-15 seconds) phone will reboot(restart)
When phone completes reboot ENTER
*7465625*638*00000000*00000000#
NEXT ENTER
#7465625*638*00000000#
AND THEN *#7465625# to check the locks,all locks are inactive.,these are all the locks...
network lock - inactive
subset lock - inactive
sp lock - inactive
cp lock - inactive
sim lock - inactive
activa lock - inactive
phone lock - inactive
auto network - inactive
auto subset lock - inactive
auto sp lock - inactive
auto cp lock - inactive
------------------------------------------------------------------
everybody know the tow company celcome and jawwal in my city
each work in 900mhz

ok the first sim from celcome company in israel the mobile work perfect

but sim from jawwal company when im try to call the mobile show

not allowed

why