Fixed telephone number "02 1" Shanghai? Shanghai?
Usually this kind of phone is a landline.
Marketers who have no demand are generally considered as harassing calls.
First, it may sell insurance.
Second, marketing calls.
Third, fraudulent phone calls.
Fourth, it's best not to answer the phone, because don't answer strange calls easily under unknown circumstances.
Fifth, hang up if there is no demand, and don't disclose your information!