well it's just like what happened to me on my poloniex and minergate account,someone trying to use forget password feature every damn single day
though he got my data from another site,maybe it's the same problem to you,however can't change the email so the only way is having multiple authentication
I also faced hacking attempt on my poloneix account , the hacker sent a message to my E-mail asking for verify some thing , the E-mail address was similar to poloneix address , so I clicked the link in the E-mail , then it took me to a site looks like poloneix , but I noticed that the site link isn't poloneix and closed the site , I don't know how he got my E-mail , however , now I am very careful , and I think twice before I register in any site and before I click any link .