I am a telecom mobile phone, but every time I charge my phone bill, I get a text message saying that my phone bill is overdue. I think it might be my traffic.

Call customer service and tell him that there may be other reasons, but you said that this situation is basically impossible, because when the traffic in the province runs out, it will automatically use domestic ones, unless your mobile phone can make some restrictions, but generally it will not. You can call 10 thousand to ask what service has been opened, or go to the business hall to run water, at a glance.