How to get Charon in Fallout 3, it's not working!!!?

I already talked to the owner of Charon's contract (Alzmenth or something weird like that) and he said if I killed Greta then I would get the contract. Well I went and killed Greta by putting a frag grenade in her pocket while she was sleeping. I know it was dumb and everyone came after me. After some time the ghouls of the underworld forgot and let me back in. Now when I go to Alzmenth or whatever it is, he doesn't even mention her death, just asks if I want to pay 1000 caps or 2000 caps. Please let me know if I can do anything to get Charon or if I've shot myself in the foot. Thanks in advance.