Please describe what hardware, Volumio version and touch display plugin version you are using. Also describe how the display is connected.
What happens when you install the plugin from the store (WebUI)? Do you see any errors? If so, what are the error messages?
If there are no errors during installation: Do you see errors (what?) when you start/stop the plugin?
You could also connect to Volumio via SSH (https://volumio.github.io/docs/User_Manual/SSH.html) and watch the live journal with
sudo journalctl -f
while you start or stop the plugin. Please post any error messages from the log relating to the touch display plugin.