Who will notify Beijing mixed-up positive SMS?

Customer service of China Mobile, China Telecom and China Unicom. After the implementation of the new epidemic prevention and control measures in Beijing, once the nucleic acid test results in the whole city show mixed positive people, the customer service of China Mobile, China Telecom and China Unicom will inform me by SMS. Those who receive the short message will be notified by the short message to the nucleic acid detection point for free single-tube detection. In order to save the detection cost, many people's test samples will be put in preservation tubes for novel coronavirus nucleic acid detection. If a positive condition is found in the test tube, it is necessary to re-examine the subjects in the tube with a single tube.