What a day!
So TM technician came and replaced the fiber cable from FTB to the modem, still same.
According to my mum, they say suspected is FTB problem, will replace the unit and need me to pay for it CASH.
They will come back tomorrow to fix it (did'nt bring any equipment)
I tested the speed this evening, its getting 1-2Mbps only.
So I just opened the FTB and saw this!

This doesn't look right, fiber not suppose to bend like this!
I just pull it out like this.

Guess what?

So ya, its their workmanship problem.
Will get receipt from them (if still need to pay), then try to get credit from Unifi.

They roll wrongly.. It's suppose to come from right side. Opposite of the opening. So the bend in not too much.