Well got your attention now.. :-/
(hopefully)
Not really hacked, but i don’t know what it is.
It is a strange problem with my Inbox.
Have a look at the screenshots I made.
This is the INBOX: it contains 12 messages.
[thumb=B]FrontLook-00142.JPG[/thumb]
Here is the SENT ITEMS folder, this one contains 8 messages
[thumb=B]FrontLook-00143.JPG[/thumb]
That makes total: 12 + 8 = 20 messages.
Now have a look at this: It says 38 messages 
[thumb=B]FrontLook-00144.JPG[/thumb]
I think the rest is self explanatory.
I’d appreciate if someone could have a look at this problem. Maybe there are more Guppies with the same problem. I only noticed it just today, when removing some old messages.