Irwell, thanks for the links, but I don't see how exactly they relate to this problem...
On Twitter they indeed show alerts of when the service is down, but nothing special was mentioned about accounts where as a result money may have disappeared.
There is one post in the service discussion though, that suggests Bitcoin-24 to be broke:
https://bitcointalk.org/index.php?topic=166456.0Could this be related? That would be scary...