Move on!
게시한 사람 Simon Lynch 속 암스테르담 공개토론
Anyone who cannot let you see a flat is almost certainly trying to defraud you. Look at it another way, would you want to rent from someone who doesn't have a friend who will help him out to show the flat or the common sense to use a rental agent if they are not there.
Trying to check ownership is almost certainly not worth the effort. If it smells like a scam, it will be a scam. Not worth the risk.