video malfunctioning

Because Zoom cannot be bothered to provide customer service to their customers, I reach out to you, my fellow customers for help.

The video quality on ZOOM CALLS ONLY on my computers has suddenly gotten glitchy. I tried uninstalling and re-installing, I tried updating, to no avail. So I switched to a different computer. I checked the quality there and it worked. Later when I logged on for a VERY IMPORTANT WORK CALL Zoom did an automatic update, and suddenly the video quality on this second computer was exactly the same as on the other computer. Glitchy and non-functioning - causing me to lose an important job. HELP!!