What is the reason why the Unicom traffic package I bought doesn't work?

After purchasing the traffic package, you need to check whether the internet access function is turned on first, and you can call the operator's customer service phone to inquire; Then see if the data function of the mobile phone is turned on. If it is enabled, please turn off the phone and restart it. If it still doesn't work, you need to call the customer service hotline and wait for the operator to handle it in the background.