What is Unicom's letter? Why do you still deduct the phone bill?

Unicom's letter service is a subscription and on-demand service based on SMS platform. After processing, communication fees and information fees will be charged. The information fee is mainly the fee generated by using the information and application services provided by wireless data service providers, which will be charged by the third party SP, such as applying for Tencent Red Diamond, Blue Diamond and Green Diamond. These are the convincing services of China Unicom. If you need to inquire about the specific deduction, it is recommended that you contact your home customer service.