Satoshi, ThomasV, and Molecular have all been affected by their GMX email being hacked? I think this is more than enough warning for those using GMX to migrate to a new mail provider ASAP, there's either a serious flaw in GMX, or someone inside of GMX is doing some dirty work against those known to use cryptocurrencies.
I agree. I can only recommend staying away from gmx, at least for now.
My best guess is some exploit on gmx that allows password reset.