Why does fiverr decrease response rate over spam messages?

[thecorex]

It has happened more than two times that the message from new buyer is spammed and there is no notifications about it and when I check it after sometime so by that time my response rate has been decreased by the fiverr. I am not aware of a message so why is it affecting my response rate because I am not receiving any notification from the fiverr about it. So either the fiverr should provide some notifications over spammed messages or they should not decrease the response rate for such messages. Kindly suggest that what possibly can be done for this because the response rate decreases fast but it takes much effort to increase it again.