I executed the command succesfull.
find / -user rbrand01 -type f -size +50000k -> nothing
find / -user rbrand01 -type d -size +50000k -> nothing
This means as far as I can see that the qouta is not correct for this user.
It keeps adding up somehow every time a mail is received.
Is it possible to set the qouta to 0 for this one user without screwing up the whole qouta system?