Uninstalling Capital One Shopping

I have tried following the instructions to uninstall Capital One Shopping on my Computer, but when I go to Safari to remove the extension, I get a message saying that the extension is part of the application and to go to Finder to remove the Application. But when I go to Finder and try to remove the Application, I get a message saying that it can't because the extensions are in use. What a vicious circle! Can anyone help me figure out how to get this uninstalled?! Thank you!!