The early PM boxes had the words "farben unverbindlich" ('colours may vary') printed on. But nowadays this courtesy seems to be omitted. I would have felt cheated like you, Tonguello, had I bought this set.
I agree with Klickteryx that some of the gold coins look more like pewter!
Tonguello, you should write to Geobra, posing as a 7-year old and expressing how disappointed you are that the Playmobil you bought looks nothing like the box picture. Really lay it on them (' I saved up my pocket money for 14 weeks, I fell in love with this set in the catalogue, it reminded me of my dead grandmother's best dress', etc.)
Worth a try?