I don't think the taking down of signs was particularly due to a complaint by the Change Office in Calis, as signs have been take down in all resorts, i.e. Hisaronu, Oludeniz, Ovacik etc., Even Colin, the clothes shop (and now Estate Agent) guy took his signs down.
I would think that probably Sedat has been reported, but they would need to catch him in the act now. He does not stand outside the shop and advertise that he changes money. However, Colin does and it makes me wonder just how he gets away with it as he is blatant.
I have read that some places that change money such as a well know bag shop in Oludeniz (which offers a better rate than the Banks and Change Shops )could be money laundering. However, I have no idea if this is true or not.
Incidentally, Gurbuz is Sedat's Uncle.