If you need to remove a company from your community, you can do it easily in community settings. After you remove the company from your community, they will no longer have access to it or be visible, but they will keep their company profiles.
Tip: You can also hide a company in your community. This means other users won't see that company anymore, and the company admin cannot see other users. But you can easily make them visible again later.
Navigate to Settings > Companies
Select the company you want to remove and click on the 3 dots to open a drop-down menu
Click the "Remove company" button
Confirm your selection
Note: if you want to add this company again to your community, you will need to send them a new invitation.