What is metabank prepaid all about?

I have a friend who says her bank account was hacked for the 2nd time. When asked what bank she uses she said Metbank Prepaid. That sounded iffy as a real bank, so I looked into it and couldn't find much on their website. Anybody here know anything more about Metabank, and what prepaid banking is? Also do you know anybody who has had their money taken while using Metabank or some other sort of prepaid account?