Div Take over solution needed

Hello. There is a website where i have inserted my html code, a competitor of mine inserted the same code and now he took over my website (i cannot remove his code). This is the code we both are using: <div style="position:fixed;width:100%;height:2000px;background-color:white;z-index:2147483647;top:0px;left:0px;"> <div style="text-align:center;padding-top:50px;"> I TOOK OVER YOU SITE! </div> </div> What i need is a solution of which kind of html code i can use so he won't be able to take over my website, please note that i cannot control of what he is adding, he can add to the button of the html page whatever he wants, i can just control the top part of the page, so i need a solution that no matter what kind of html code he is inserting, it won't be shown.