I cant undo the hinge nut on my ghds?

I have the mk4 pink ghds, i stepped on them the other day and broke them in half! gutted, they seem to have broken off faly cleanly though and if i could get the broken bit off the hinge nut i could glue them back on and hopefully they will be good as new, i cant how ever get the hinge nut undone! its like some super strong man in the factory tightened them up before i got them, is there any reason why ? My boyfriend has tried too so its not just me that cant do it,