Be sure to press on the white push release button at the same time as removing the filter by pulling the plastic tab

Turn off the water supply to the Water System using the blue and white isolating tap behind the machine.

Place a cup under the spout and press for cold water (a very small amount may be dispensed). Then try to remove the filter.

Using a blunt edged tool (e.g flat screwdriver) try to lever the filter out of place whilst pressing the release button.