The most likely cause of a lower Courtesy Rating is an Internet connection incorrectly setup for eFootball PES causing an unstable or weak connection to the game, which can lead to disconnections. If you're having trouble playing online because of disconnections, we recommend that you check your Internet connection and any settings related to it as, once it is set up correctly, you'll be able to reach the A rating in no time by playing successful games. You are the only one who can regain your Courtesy Rating since we can't change it for you, as explained here and after that you may even reach the AA or AAA rating!
Please be aware that other players’ disconnections do not influence your Courtesy Rating in any way and also that any cheating experienced in eFootball PEScan't be related to your Courtesy Rating since it is the Courtesy Rating of these "players" which is affected. The Courtesy Rating is the first step of actions against troublemakers and their disconnections so please visit our article on how to make your connection smoother as your Courtesy Rating is only linked to your connection.
To check the status of the server in real time, you can visit the web page http://www.konami.jp/we/online