Ordered a 50-500 lens from Sigma and agreed price for 6000 hong kong dollar. Suddenly it could not be delivered but I got aso called better alternative offered for 8000 Hong Kong dollar. Afterwards I checked internet and the value of these"better" lens wat not even half the value of the 50-500 sigma lens. We brought back the lenses but credit card payment was not cancelled. This is how they stole 800 Euro from us. The Police could not do anything and is protecting (probably bribed by the shopkeepers).
This shop is a pure criminal organisation, so they only advice I can give you is never to buy in this shop or order by internet from this shop. I lost 800 euro, stolen from me, so let not something like this happen to you.