Why is my phone bill 18611 marked as fraud, which makes me a little worried? Why?

It's a customer return visit of Beijing Mobile and Taian Mobile.

If it's a short message calling users, it means that someone called you when you turned off your phone or when there is no internet, and you only received this information. If it's ... information about winning a prize or buying something, it means that someone used the internet to make a number like 186 to mislead people to cheat money. . It's better to be careful

set it as a blacklist to see if you don't reply to the text message.