Data stays on even when I turn off Mobile data - Note 3 SM-N900V

[AC Question]

Hi There,
I have a Samsung Note 3 (SM-N900V) originally Verizon and now using T-Mobile sim in it.

I see that even after I turn off my Wifi and Mobile Data, I can use Internet on it.

There are 3 modes under Mobile Networks:
1 - Global
2 LTE/CDMA
3 - GSM / UMTS

This happens when I have any one of the 1st 2 selected (and I do not get proper cellular coverage when 3rd option is selected).
Already tried removing the Wifi - Auto network Switch option.

This happens only when I see a 4G-LTE coverage, the mobile data icon stays deactivated when this happens and I see a 4G-LTE (greyed out option next to the signal bars). Tried resetting the phone too.

With this problem the only option I have is either silent it or Airplane while sleeping, in both cases I cannot get/notice any calls made to me in case of any emergency.

Is this a known feature/problem. Any suggestions will be much appreciated.

Thanks,
Ajmal