Every time I answer the phone, I get a text message.

Probably using a smartphone. Many junk applications will steal number information and send it to specific SP vendors. In this case, there are several ways to handle it:

1, bear with it.

2. change the number.

3, the situation is not very serious, brush a clean bottom package, do not install those junk applications (saying that there are very few applications that do not sell personal information)