How best to ask LG for new 5120d firmware?

I’ve seen posts indicating that email to LG customer service is not effective. Can anybody suggest a better method of communicating with LG. I can’t understand why they’ve let the firmware for the 5120d fall so far behind the 4120b. I know there is an unofficial converted 4120b -> 5120d A112 firmware available but why doesn’t LG release something. How best to request this from them?

GSA-5163D firmware is also missing whereas there is GSA-4163B A101 firmware available on LG sites.

I thought that the GSA-5120 was a GSA-4120 in a external enclosure? Isn’t it the same firmwares?