To clear cache on Firefox follow the steps below. If you continue to have issues please contact us.
  1. Click the Firefox menu button (three horizontal lines) and choose Preferences
  2. Select the Advanced panel.
  3. Click on the Network tab.
  4. In the Cached Web Content section, click Clear Now.
  5. Click OK to close the Options window
  6. Close the about:preferences page. Any changes you've made will automatically be saved.

You can find more information on clearing your browser cache at the Mozilla Firefox website