Fake evaporating perfume from Myperfume shop

Worst ever, I bought 2 perfumes that evaporated the moment that you put them on.I sent them back to Cape town, instead of them giving me my full refund they are trekking me they'll take 20% because the box was open. Like how was I supposed to know that it evaporates and you won't smell it on your hands after 2 seconds if I didn't open the box? I'm suspecting that they are selling fake perfumes as both perfumes did the same thing. I've subs since bought the same perfumes from woolworths the packaging of the one perfume from the my perfume shop lools different. I'm utterly shocked and dissapointed.