a magazine calls ”seventeen”

You are referring to the magazine for teenage girls, right?

you can buy it at a lot of places. bookstores like page one, dymocks or at large supermarkets like city super, great, gourmet. HMV sometimes have it too, but it sells out real soon. suggest you go to Admiralty and try find it, there is a place that sells magazines and they have it. (at MTR HMV's level)

Try to buy it on the first few days of the month because it is published in US at the end of the month and it takes time to airmail it to Hong Kong.

Hope this helps

大嘅英文書店如Page 1, 晨衝, 金融中心的書店, 有時尖沙咀碼頭, 中環啲報紙檔都有.