I called samsung Pakistan and asked about this issue.
They told me that ZONG is not included in the list of 4G operators, thus 4G option does not enables on zong sim.
and an update for note3 and note4 is on its way for Pakistan.
I have S5, so he said, samsung Pakistan hasn't launched 900F s5 LTE model, so we can't officially request Samsung Internation to release an update for 900F with 4G operator addition