Just to update - I recently got another Pantas SIM card , for my son to put inside his smartwatch (cheap one lah, not the Apple Watch or Samsung Gear) .
The watch itself is 2G based , hence its only capable of making calls , track movement (via Cell tower location, not GPS type) and sending voice messages . It cannot do any web browsing .
Here is the thing I so far experimented with 2 scenarios
1) My SIM card with data quota - Yes it works, much faster.
2) His New SIm card - Credit Validity expired - No data transmission at all.
3) His New SIM card, without any data plan, credit validity active - It works, but data transmission (Upload & Download) is delayed, by minutes.
Furthemore I can see the tracking movements still being updated , even w/out data plan.
I have experienced myself whereby, my HotlinkMu 8GB data quota finished earlier ,1 day before expiry, and it continues to work.
However earlier I have tried the 5GB pass (the 365 days type) , and the moment I finish the quota, it stops immediately, like someone yank the handbrake.
So this some hidden feature, that I discovered.
You guys can try it for yourself.
I'm so out of touch.