According to the blockchain explorer I still got 5600 nxt in "Balance", "Unconfirmed balance" and "Guaranteed balance"

This indicates that there's something wrong with your client as your account still holds your balance.
Download the latest NXT NRS version 1.2.5, fire it up, let it download the blockchain and log in to your account. You'll find your 5600 NXT sitting in your account.
https://nxtforum.org/nrs-releases/nrs-v1-2-5-4412/It's working now. Although, I used this client:
Thank you.