I've asked @Aggre to explain the feedback.
But actually I already kow the answer:
The user was not happy so he left a neutral feedback...
Why Should the feedback be removed if it's true? It's your job to keep your customers happy.
Sorry for the late repsonse, I'll see if I can have it added.
Randoms can be disabled in the client, Settings-> Options-> Dismiss all randoms
Ya i'll be taking a look at the cannon support.