Block IP address of web proxy on Zeus server

Web security issue. My site has been viewed through a web proxy and as a result Google is now indexing a duplicate site - my rankings have plummeted as I am penalised as having duplicate content even though I own it. Need help to identify and block that IP address (or range) but simple fixes found online (to edit .htaccess) are not possible as we are on a Zeus server. Need urgent experienced and knowledgeable assistance - as we cannot support a learning curve within this job. Getting no help from our hosting provider's support team who don't seem to have this knowledge.