The problem is, that I can't use my wallet at all right now.... that's kind of terribad 
Every transaction I do, even after I got some new money in, won't leave the wallet...
Is it because he eventually transfers some of it from the "ghost" btc?
Every transaction I do, even after I got some new money in, won't leave the wallet...
Is it because he eventually transfers some of it from the "ghost" btc?
Probably yes. What you can do is Settings->Wallet->Enable Coin Control, restart core, then you can specify exactly which coins should be used when doing a transaction. Just tick the addresses at which your new money arrived.