the flapper is now blocking the hose. we got a screen or something in our filler tubes to keep thieves out of the tank. that flap i bet is laying over the screen.
the pump turns off because the filler neck is filling up and the pump quits pumping, the funnel is a much slower fill.
id check another car and see if its brass or not, aka will a magnet stick to it. if so try to fish it out with a long magnet, or one on a string maybe.
if it dont stick to a magnet its time to take the filler hose off the tank.