The tailgate on my 03 A-class won't open... Although the handle moves fine, the internal mechanism doesn't 'pull' far enough to release its hold on the striker pin bolted to the rear sill. Having removed the trim panel, from the inside I was able to open it last week by pushing and wiggling a screwdriver. Now, having returned to try to fix it, I can't open it at all - despite manually levering the nylon slot into which the ball of the release cable attaches. Suggestions appreciated - please/thanks, etcetera.