Asked before even technician also came to my house and told me it's above their 80% promised speed. Then I asked what about my previous speed when I got 32-33Mbps, technically it has reduced by 4-5Mbps, they said what I got earlier was just a bonus.
Well, luckily when I complained few months ago, TM hasn't started charging service charge of RM 53.
Nothing much can be done except I get lower than 24Mbps.

The thing with 28Mbps is you can't make it as a case though one may argue that MCMC's regulation is 90% of promised speed which is only 27Mbps and 28M is above it...