Sorry to hear this. You can disable the icon if you need to. When you open the add-on panel, click the gear icon to go to the "Settings" panel. Turn off the switch that says "Show Relay icon in email fields on websites".

Sorry to hear this. You can pin the icon in the menu bar: https://support.mozilla.org/en-US/questions/1411702

You might check out relay.firefox.com which has "Help & Tips" and FAQ?

Hi thank you for the report, I'm sorry to hear this! Can you please share what your email provider is and some of the websites that are not working? If you would like to share with our customer support team you can open a ticket: https://support.mozilla.org/en-US/questions/new/relay