I don't see a question here, are you trying to use your TV remote on the sound bar? That likely won't work unless your remote happens to have codes to program the sound bar. If it has a learning function you can try that.
Sound bar is connected and works. However, when I change channels with TV remote, it also increases/decreases volume with each channel change. So need to use sound bar to return volume to previous level. Maddening!
Are you saying that chaning channels acts as "change volume" on the sound bar, or you are saying that eg Channel 2 volume is lower than Channel 4 volume, so you have to adjust it while channel surfing?
In first case - you have a piece of BS for a sound bar. In the second - that's the life, and there's nothing you can do.