[haus]

They're not hacking your phone as much as testing your email to see if it's valid for future spamming. My strongest, heartfelt, honest recommendation is that you never mess with it. Sorry for not giving you the answer you want but I believe very strongly that my answer is more helpful to you.

In case you don't know how it works: spammers tag individual email image links with codes that are unique to each email address. When their web server records a hit on a specific image URL, they know an email client application somewhere has opened the message and bingo, that email address becomes much more valuable to spammers. It's a lot easier to hard reset your phone than it is to change your email address (at least for most people).