An advertisement for e-commerce retailer JD.com Inc in Shanghai. [Yan Daming / For China Daily]

China's biggest iPhone distributor Unicom Vsens said on Monday that it never sold any refurbished iPhone products to retailers in China including JD.com, which was caught in a spiraling fraud scandal recently.

Unicom Vsens Telecommunications Co Ltd, a fully-owned subsidiary under China Unicom, reiterated that all of its iPhones are authentic products from the Apple Inc, as the company is an authorized distributor of the US tech giant.

The company said it is willing to cooperate during the investigation.

According to CCTV's Weekly Quality Report, JD.com has been accused of selling refurbished iPhone products on its website.

The accusation has caused some buzz on the Internet. JD.com responded on Sunday that it promised reliable supply sources and vowed to conduct a thorough investigation into the case. One day after JD.com said the phone in question was sourced through Vesens.

Some possibilities could result in a refurbished iPhone being sold on JD.com, including lax supervision by the two companies, and customers maliciously returning products, said the National Business Daily, citing an insider.

The insider said, Vsens as an agent not only sells iPhones in China, but also provides repair and sales return service; so some used iPhones may move from its repair sector to its sales channel for selling; and the refurbished iPhone also could be from other suppliers of JD.com.

However, neither of the above has been proved by the two companies.

Because of JD.com's negligence to check the return, some speculators could return a refurbished iPhone instead of authentic products, the insider added.

JD.com said items returned by customers would not be resold.