Amusing as it may be, the name-calling is not helping your position.
It matters not. It is hers. You said it yourself, she was the one who made the agreement.
'Offing' you would not benefit me, and I have no need to do the world a favor by removing you from it. Hell no longer wants you, William. And, as you have pointed out, you are a vampire. You lack certain attributes. Ones that Miss Summers possesses. A pulse being among them.
You are useless to me. Unless you can change that within the next forty-eight hours, I have no business with you.