It may be true. I have received a call from China Merchants Bank Credit Card Center selling insurance, but China Merchants Bank first sent a text message to notify the caller number. So you have to first check whether the caller number is Shenzhen Development Bank. Yes, it would be more suspicious if it is a very common number.

If you really need insurance, you can ask him to call back later. Then remember his calling number and call the customer service of the credit card center. They will help you check if there is such an activity and verify it. If you have confirmed that you need to buy insurance through them, be sure to remember the date and time at that time. If possible, record the phone call. It is best to ask them to send you a written policy or policy afterwards. Other written certificates are used as proof. They said that it will take effect verbally without signing because the calls at the credit card center are all recorded. This is used as proof.