Incomprehenible change of rank by moderator crodgers

My rank was suddenly changed from 21K to 8K. When I started to play live my rank was 14K. I don´t remember why. Perhaps because I had played a lot of time against the machine. Playing In the “real world” I moved downwards until I reached 21K - then my rank suddenly changed to 8K, and, as it showed afterwords, I don´t belong there. Again I fell to 21K. For a long time I have moved forth and back between 17K and 20K - now 18K. It is a bit disturbing when I have to explain to other players why there is this mysterious peak in my statistics. In the “real world” I have never been better than 17K. Is it possible to change it?