Acer G277HL 27" IPS Monitors (multiple) no sound / speakers not working using hdmi

hi,

Bought 3 Acer G277HL IPS monitors recently. Currently have 2 setup on one computer. Display works fine, and I normally use a headset, but cannot get the built in speakers (which are supposedly there on the ISP models) to work at all. Zero sound.

This is despite the fact I have
-tried to update drivers
-yes the devices are on, i tried restarting everything
-sound is not muted from computer, comes through headset fine.
-hdmi sound supported by graphics card- proven by my old monitor working fine for this
-the computer is set to default playback, all other devices disconected

When i do sound tests and look at the volume mixer, the bars jump as if sound is going through the monitors, but i assure you none is. 

Odd thing, the volume on on the monitors menu is unclickable. the button does nothing at all unless in another menu, where it is an arrow-over button. 
I feel like this implies there are in fact no speakers in the monitor, dispite there being small slats on the monitor which look like speaker spots. 

Heres a link to the exact monitors listed on a different site than where I bought them. https://www.elive.co.nz/acer-g277hl-umhg7sa-003d10-zero-ips-monitor-speakers.php
Bought on NewEgg where it does not actually say it has speakers https://www.newegg.com/Product/Product.aspx?Item=N82E16824009735

Is the monitor sold with and without speakers (but same exact model)? I dont know. 

help pls