I don't wanna sound stupid but do u use the right tool? Good phillips size? As you said the trim is already broken so you can cut the two notches just besides the srews and remove the trim pulling backway. Try using loose nut for the srews.

Nic.

Contour 99 MTX V6 fully loaded, stock with 110000km. Illuminated sunroof switch. About to do the mystique rear dome light conversion with eyeball dome light.