If you know the URL to your App catalog or are using a site collection app catalog, you can skip to step 5.

  1. Login to your Office 365 admin center page with an administrator account;

  2. Open the app launcher and click on Admin;

    Admin Center.png

  3. Open your SharePoint Admin Center;

    SPFx SharePoint.png

  4. On the left pane, click on apps and then App Catalog;

  5. On the left pane, click on Apps for SharePoint;

    APPs for SharePoint.png

  6. Select the older package of the Web Part deployed, click at the option Files, in ribbon, and click to Delete Document;

And that's it! The web part is now Uninstalled and Removed from your SharePoint site.