Yes, you do. Here is why:
These guys have your email address and hashed password. If they crack that password, which they very will might, they will sell it to people who go and try that same email address/password combination on Facebook, email providers, banks, internet shopping sites, and more. They do this because so many people use the same combo over and over. Sometimes the hackers publish the list on the Internet to hacker sites for free, which means that any mischief-loving kid who can run a script will try to see what they can get.