Except for the official telephone numbers of 400 well-known companies, more than 90% of them are liars, but the chances of the truth coming out are too small.

Because this kind of phone can't find the attribution and the real name of his company, I absolutely ignore the 400 calls I saw on the Internet.

You can also sound it out and ask him if there is any phone with area code besides the number 400. Liars will definitely say no, and regular companies can't have no phones with area codes.