Grandpa tries his new smartphone at a park in Beijing on Nov 6, 2015.[Photo by Song Jingli/chinadaily.com.cn]

Half a month later, a post-sales woman called me and asked me in a very soft voice why I had returned the Nubia phone. I explained and she said "We will improve our products."

At last, my father-in-law chose a Huawei Honor 7i smart phone, because it, with a rotating camera, was really different and my mother-in-law's phone really made a good impression on him.

The phone-buying story, which lasted for more than 20 days and finally came to an end, has greatly enriched my whole family's understanding of the smart phone industry in China.

But what is intriguing enough is that both the grandma and the grandpa are not the targeted consumers of these two types of smart phone, who are assumed to be youngsters in favor of "new, cool, fabulous" things, according to the advertisements of Huawei.

It happened that the Nov 11 shopping festival created by Alibaba but used by all online retailers to promote shopping, also took place when we were "buying" phones.

When you check the top 10 merchants on Tmall, Alibaba's B2C platform ,on the shopping spree day, you could find six were smartphone vendors or dealers, including LeTV, Meizu, Huawei and Xiaomi. Xiaomi, the rising star in the smartphone industry, defended its crown as the top seller by raking in 1.25 billion yuan on this single day. Its Redmi Note 2, priced at 699 yuan only on that day, was the best-seller among all smartphones.