Samsung Galaxy S4 (SHV-E330K) - Roaming

[ScyberMhaster]

I have a Samsung Galaxy S4 Korean Variant. I live in the Philippines, and I believe that this phone is unlocked because I can use my SIM Card to it (Globe Telecom - Philippines).

Now, my problem is when I turn on Data Network on 3G / 2G.

Whenever I turn it on, on 3G mode, not LTE because the area was just covered by 3G, I notice in the notification panel that instead of seeing "Data Network", I see "Data Roaming".

So, there's no way to turn off my data mode. And when I go to the Messages, there is a warning that says:

'Roaming... charges on receiving text... etc.'.

And on the notifications, when I pull it down, it says 'Current network: Globe (51520)' something like that. And when I click it, I will go to Global Roaming in Settings. And sometimes, there is sometimes signal drop and it losses connection from 3G to 2G then vise versa, and sometimes it says 'Insert USIM to connect to etc.' or ''Insert SIM Card to connect... etc.' but on a couple of seconds, there comes again the signal for my phone.

However, if my phone connects to LTE network, it works fine.

Samsung Galaxy S4 Korean Variant
Android 5.0.1 Lollipop

[ScyberMhaster]

Hey guys. Please help.