That the surprise itself.

if tm cant upgrade the speed due to infrastructure "limitation", better half our monthly fees while maintaining the speed then.

A typical user can be happy with an average of 10-15Mbps.
For me, a 10Mbps with good latency satisfies my hunger of BW.
Talking about those days dial up, you happily using and your housemate complaining of waiting to make call to their parents. Epic

In Japan, Softbank have decent speed. They are quickly rolling out TDD spectrum and some places they have launched pre 5G solutions which boast your speed much higher. You got to take into account of the congestion. This is pretty subjective.
In China, unicom i was getting in average say around 30-40Mbps (on CAT 6 phone).
Of course mobile network nowadays giving speed above what we getting in fixed line in Malaysia. (talking about sub 30mbps). Which is sad, considering fixed line have more controlled interference compared to wireless.

Upgrade from 10Mbps to 30Mbps not yet started i guess? :-(

ohhh...didnt know ppl here butthurt about this.