Scam in Hong Kong

Few weeks ago i was in Hong Kong and everything was cool till i was con by one medical hall shop. Here's what happened.

In Tsim Sha Tsui, i walked pass a medical hall shop that sells Abalone, Shark fins etcs and decided to walk in and take a look. No intention of getting any stuff at all. Once i entered the shop, the sales assistant came over and tried his best to sell me some abalone. I patiently listen to him and he pursue me to purchase some abalone which he told me 10-11 of them cost HKD$680 which is very reasonable and on top of that he will give me a package of free shark fins. WOW~ as a consumer, it's one of the best deal ever! My mum is the one who always buy all these stuffs for my family so i thought this time round i can buy some back instead. I did double check with him whether HKD$680 will be what i will be paying and he said yes.

The shop assistant keep insisting i should slice all the abalone into slices and he will pack very nicely for me. I didn't want to slice them up in the first place but the shop assistant was very persistent therefore i gave in. After slicing all the abalone, i wanted to make payment therefore i took out a thousand dollar note plus $80 dollars worth of coins, thinking of i will be able to get back $400. The next moment, the cashier asked me to pay the remaining amount by credit card. I was puzzled and to the shock of my life i was told my purchase was $10k over instead of $680. I argued with the shop assistant for almost an hour because the whole incident was a scam as from the beginning till the end i was not told how much my total purchase was. The only amount mentioned was $680 and nothing else. When i asked them to return me back my cash, they refused! At the end of the day i was force to buy a few slices of abalone at $680 as i don't wish to argue who's in the right or wrong anymore since the shop refused to admit their mistake.
By the way, those slices of abalone taste like cuttlefish. Highly suspected it's fake!
Readers, please do not step into any of these shop when you visit Hong Kong. I did a detailed research and found out there's alot of tourist are being cheated too. BEWARE!!