Local branches of China's top three mobile phone operators in Shanghai have offered new data packages that can be used for three months starting in January, after the phone giants came under criticism over their monthly data charges, Beijing Times reports.

A customer named Liu Ming in central China's Hunan province first brought the issue to light by filing a lawsuit¹ against the Changsha branch of China Mobile. Liu argued that the company's practice of clearing the remaining unused data at the end of each month without offering a refund² or extending it to the next month was unjustified.

Liu had bought an online package for 20 yuan which entitled him to the use of 150 megabytes per month from China Mobile in June, 2013. But at the end of July, Liu found that he had 92 megabytes remaining as part of his monthly package, though that amount would be cleared to zero in August.

The case sparked debate among mobile users nationwide.

The Shanghai Consumer Rights Protection Commission carried out a survey in July, 2013, which revealed that about 54 percent of respondents said it was not reasonable for mobile operators to clear unused data allowance. The commission spoke³ to 2,000 people across a range of age groups.

Since January, the three mobile operators have provided consumers with a quarterly data package. However, mobile operators in Beijing said they are still discussing the case with no final result yet.