How do you complete impcatcher on RuneScape

imp catcher is a good quest so here is how it goes

1.talk to the guy in the top floor of the wizards tower (the one next to draynor village)
He should ask you to recover all of his stolen beads from imps

2.kill all the imps possible and I would say 1 out of 30 drops you would get a bead or you
could do it the easy way and just buy them off the grand exchange

3.with all the beads in your inventory go back to the wizards tower and talk to the guy again,
a cut scene should follow where he takes the beads and puts them in a bowl and if they are the right beads he should thank you and give you an amulet of accuracy (worth 14k) and you should get 1 quest point