Remove GoPetition Account Completely

Select a reason for closing and it'll take 2 clicks. 

How do I remove my name from "GoPetition"?

Two years ago I signed two petitions against some executions with my full name and surname.  Who ever type my name on google finds what I signed and what I wrote in addition. The thing is, ppl have judgemental perspective about  my comments and I found myself too open with that  two signatures on the  "WWW".

How do I remove it? I tried everything, but it seems that it is somehow "frozen" on Petition Templates, Samples & Examples | GoPetition  If you sign something in a petition, it stays a whole life like that and you can't make it anonymously even after the case is ended.