I'm not sure who ACID is, but apparently she's a collecter. When you click on her, it will show the wants and rewards, as you've stated. In the Wants section, make sure you have the required number of keys. It should show the key, then (7/X). 7 being the number of keys you have, and X being the number of keys you need. If you have enough, then u can click the button that says TRADE below the wants. If you dont have enough, get some more keys.
