My LG TV will be 4 years old in August. Yesterday the HDMI/ARC port stopped sending sound to my soundbar. I swapped HDMI cables and tried a different soundbar but the problem remained. This morning I live chatted with LG support. They readily took all the details and have sent the job to a local repair company. Al at no cost to me. I didn't have to mention the CGA at all, they just got on with it.
All too often companies try it on and say things are out of warranty so you are on your own. Not so with LG. It sucks to have the problem but these things happen. Big ups to LG for their customer service!