As above, there is a lot stupid cut-off their line but the system don't update, because their method of cut-off is, stop paying it....
So by checking the system, they will unplug those port that is marked long time unused/unpaid.
Or, there is a backup port, or they planned to extend for more customer to be covered la.
This is explain by others a few old topic thread vN la.
---
For my case, that house got 2 port binded, first one is a stupid that stop paying and holding the port + address, second one is normal port that is empty but under different address.
I think/guess...
Somehow the installer unbind the stupid port, then use the second port that is empty(and longer fiber in house), and bind my port as stupid first port.
So that celcom/maxis guys see it is long term unpaid port in system, choose to unplug mine and plug in their, lol.
As I saw the repair guy coming in, connect back my fiber to the port, and stay long in his car clicking the tablet(15-30 mins, so long lol), I guess this should be the case, lol.

Thought this plug and unplug thing is the job of TM contractor? Do they now allow Maxis/Celcom tech to simply come and mess with their DP?
I got sms that my speed has been upgraded from 300 to 500 last week. But I checked mine still 300mbps. Any issues?
Quite possible botch upgrade. You have to lodge report and ask them to configure your account with the correct speed.