I used their service to track lost inventories and got 520$ back, paid only 40$ for the service. I had to wait few days for Amazon to respond to my case. I am also using their chrome extension to find reviewers fast. Overall experience is great, i had some difficulties with the extension at first (misusing error) they went online on Skype and helped me out.
p.s You should give them a try if you have descent sales for a while and you haven't done that before, i am positive you can get several hundred dollars back.