Wah. You get cheaper than me by RM100 

This might be silly question to ask you but have you enabled the HDMI-CEC option on your TV as this feature usually turn off by default.

I forced my TV and soundbar to use HDMI output/output instead of using PCM/SPDIF

You might want to try to change the HDMI cable as well because last time I use HDMI cable given by Sony for PS4 to connect to a samsung TV and it doesn't work. If connect to Sony TV using the same cable to PS4 it works. I have to use third party HDMI cable to connect samsung TV to PS4 and then after that I manage to get the video and audio output on the samsung TV

I don't have much experience anyway. I just lucky TV brand same as the soundbar brand

Bro., Your RM1999 is 1 year warranty or 1+2 years warranty?

Cheers!

What source are you playing?

Also, have you done your calibration yet? Understand that the included mic isn't really very good, it's better to manually set the audio levels by using a sound meter.
1. I explained before not to rely on HDMI ARC/CEC. It doesn't always work and this is exactly the prime example of it. Are you very sure you connected to right HDMI port on your TV though? Not ALL HDMI ports on the TV supports HDMI ARC, so you need to make sure you connect to the correct one.

2. Or why don't you just connect everything to the soundbar via HDMI instead? It's much better as you won't have to deal with audio delay.

3. That was generally the case a couple of years ago. But like I said, don't expect or assume HDMI ARC to always work flawlessly because it doesn't. Applies to every soundbar and AVR out there.