When I tried inserting my Hotlink simcard to use up the 500MB, I can't seem to find the Cellular Data Network option in Settings so that I could key in the username and stuff.

But when I insert my DiGi simcard, the Cellular Data Network option was there and I had to key in the details. :/

Oh! Thank you so much.

So I tried surfing with my Hotlink simcard, but it tells me that I'm not connected to the Internet. D:
I did receive an sms telling me that my 500MB service is activated. Help?

Nope. Doesn't work.

After using an application, does pressing the home button quit the application completely? As in like it's no longer running in the background.

So, I was in McDonalds trying to surf the web via WiFi. It detected and connected to the WiFi connection fine.
Thing thing is, when I tried opening Safari, it won't load! It says something like "Safari cannot open the page because it cannot connect to the server". All I know is that it's telling me that it cannot connect to the server. I can't load any pages at all.

Should I be worried? :/

You're right. Apps that require Internet doesn't seem to work either. But I don't see how it is not connected to the Internet when people there got to surf the web using the laptops.

That pretty much clears up a lot. Thank you!