Ha I did that when I first got mine...
you can either take a cover off the reel easily to then allow it to be pulled out, or you can see it now, or you can unscrew the reel entirely which allows you to move it forward to pull it back! I can't remember which though!!
I THINK I had to unscrew something to get at the lever to allow you to unwind the damn thing...it baffled me for a couple of minutes then I figured it out,
IIRC...have a poke with a screwdriver and see where it gets you! And remember to pull the plastic bit through the cover thing after so it can't happen again!!