As said, you need to consider all the factors.
Just say, without this solar panels, you are spending rm200 for your electric bill monthly. But once you install this, you may only paying rm150, for long term it is something.
But for just investment sake, I think it is not that good.

The installation wrong, maybe?

Sheet
I see the wrong one. Solar panel heater won't absorb much like those solar panels.
Yours only cover 10-20% while the other type can cover 50%

Try to pay them a visit inside and see how

Under warranty or not your house?
How you wire the air cond?
Bull sheet. Ask him to fly kite
If the wiring of air cond are tapping from 1 of your plug point and you are using non inverter > 1HP type, you will be busy reseting the MCB and later busy fighting fire.

I think more on looping work

Nope, this is what most wireman will do, cheating people

Yup, that's why I also think to get new house or not, because my wireman don't want to do already

I have to work, so hanky panky will happen during this period

No point on doing this, in some sense

That is because they want to do free advertisement in forums.
Just make 1 car with some effort then other cars take back the effort.
History are proven this, KL's some reputable shops are giving sheet type of quality.

Have to lodge a report to local council already, as they are doing illegal business.

Ok, good luck to you. If the TNB technician only change the fuse rating, I suggest you to sell your house.

Any reason for this? Older housing area mostly are using single phase while newer housing area they are using 3-phase.

4 wires to the meter will be 3 phase, 2 wires will be single phase.

Yup, another way also.
An d here another : 3 phase meter will be bigger and more fancy

Single phase meter only have red LED that blink.
But 3 phase meter got green color display during night, can check voltage(mine highest was 255V during normal run) and current
Is good to have a check on incoming voltage every now and then. A rm38 Sunwah multimeter is a good start. Or if you are fanatic enough, a Fluke multimeter

rm38 only mah, can check others also
And because of this I know my voltage at 1 time at 259V, just because of connection issue on the meter.

Check for any open circuit, check voltage on plug points.
Anything > 245V, I'll call 15454.