Regarding Market function on shopify, not the country but still being default in other country

[Cath_y61]

Dear Sir,

I just set Market function on my website, with Hong Kong, Taiwan, Singappre , and England.

However, when some hk customer who is now in hk, the website shows automatically in TWD for them and checkout with TWD.

Any way to fix? As this will affect my pricing strategies toward taiwan. I want to set cheaper price for taiwan customer. If they can choose location, some hk customers will delibratly choose to use twd which we dont prefer.

In mobile version, the currencies column is at the bottom, which visitor rarely go down to change currency. 

Thanks!
Catherine