I usually wind up getting earphones at the chain that used to be called fnac, 法雅客, fayaque.com.tw
They've got a range of Audio-Technica - certainly better than Carrefour's. However, in the past I've found it utterly hopeless to try to shop by online reviews. I'm not sure if product numbers are different here, or if there's just a horrible selection in Taiwan.
And sorry, but if I'm reading their branch list page correctly, they don't have a shop in Yilan.
Their bluetooth earphones: fayaque.com.tw/product/list/ ... 7961717565
And more earphones here: fayaque.com.tw/product/list/type/audio
Oddly, I can't actually find any Audio-Technica brands listed there (only looked quickly), although they've certainly got quite a few of them hanging up on the wall.