New Samsung Q750C Soundbar Issues

Hello, I am reaching out before returning this to Bestbuy. I have it connected via HDMI Arc. The sound quality is great when working but the sound keeps going from normal to a tin can weak sound, then back to normal. I have tried adjusting from adaptive to standard to surround. I've adjusted trebel and bass etc, I've tried soundbar only and soundbar+TV. I've tried turning off/on unplugging/replugging HDMI and power cables. It is plugged in to a brand new Samsung Q70C TV. It was $579 at Bestbuy. I would consider paying a little more for something that works but prefer to keep Samsung to Samsung TV.

Thank you very much :)