Celcom seems to have the most hiccup in terms of rolling of VoLTE. On top of that, some users on older plan reporting Celcom refusing to activate VoLTE for them and suggested plan upgrade.

Looking at the Jendela roadmap, possibility of extending the sunset of 3G network is practically zero. In fact, Celcom already shut down their 3G network over the Klang Valley about a week ago.

Well to begin with, unless your plan comes with SLA I doubt you could get compensation in the form of bill discount. On top of that, MCMC minimum network quality standard was pretty low to begin with. In any case they didn't meet the standard and MCMC received a complaint, the mobile service provider are required to attend to it but even then if improvement is technically impossible (typically in urban area) the case will also be closed without a solution.

I'm not discouraging you to lodge a complaint here but majority of the complaint went without a solution (typically urban location).

Some of the MCMC members already had conflict of interest by having position in mobile service provider. This pretty much sums up what you need to know.

Both of them could still form cartel.