Upvote:1
I don't think you are in Yunnan Province anymore. The only Jincheng I can find (晋城) is in Shanxi Province (山西).
In a similar question, I linked the Chinese version of the popular Western website Yelp, called Dianping. For reference, the Dianping site for Jincheng is: http://www.dianping.com/jincheng
Unfortunately, no one is really using Dianping in Jincheng, besides the shop owners who have listed themselves. I've searched through for coffee shops, tea shops, party/game houses, KTVs and restaurants.
This place, found via Baidu.com (Chinese Google), seems like your best bet: 湖滨1950咖啡厅 (http://jincheng.55tuan.com/goods-6de9181aebf2012f.html?from=daohang-renrenzhe-tgny)
They probably have wifi, as they promote themselves as an upscale, Western-style coffee and tea house. On Dianping (under a different name) it was reviewed as being "expensive" and "exotic."
Sadly, nothing actually says they have wifi, so you'll be going on a bit of a lark. But that's what I'd do if I were you.
Location: 湖滨1950咖啡厅 (Húbīn 1950 kāfēi tīng) -- 晋城市城区泽州路1855号(市邮政局对面湖滨花园酒店1楼咖啡厅)(Shānxī shěng jìnchéng shì chéngqū zé zhōu lù 1855 hào (shì yóuzhèngjú duìmiàn húbīn huāyuán jiǔdiàn 1 lóu kāfēi tīng)
Translation: 1855 Zezhou Lu, across from the post office on the 1st floor