Mobifone codes / refill questions

Hi, i'm new to Vietnam and have a few questions about how Mobifone works.  I purchased a custom phone number a few months back and paid about 300d at a local phone shop.  I used the phone frequently for primarily surfing the internet, watching videos, etc.. for the past 3 months without having to refill it or anything.  I rarely use the phone for SMS or dialing numbers. 

A few days ago, I received a pop-up and message on my phone that i could not understand since it was in Vietnamese.   And then this morning, I was no longer able to access the internet .. apparently because I needed to refill my account (i was redirected to a mobifone website that  said i ran out of funds).  I went to a local shop and purchased a refill card for 100d and added it to my phone and then restarted it.  Internet now works, but I want to try to understand the phone codes when I enter in *101# for future reference:

1. This is what *101# showed me before I refilled it:

MobiQ
TKC:30d,03/03/2017
KM2:136564d
KM1: 28200d
TK KM du tru: 60000d, HSD: 26/04/2017 KM4 144867d.

2. This is what *101# showed me when I refilled it:

TK chinh cua quy khach co 100030 VND duoc su dung den 03/03/2017.

3. This is what *101# showed me after I refilled it and restarted:

MobiQ
TKC:30d,03/03/2017
KM2:136564d
KM1: 28200d
SMS:100,01/02/2017
Thoai:100p 0s,01/02/2017
TK KM du tru: 60000d, HSD: 26/04/2017 KM4 144867d.

Going from #1 and #2, the only difference that i see is for SMS and Thoai.  I don't see anything that talks about internet usage and the balance that I have remaining to use the internet?

Please help!