Doubt is a kind of commercial behavior, which seems to have been seen in Zhengzhou. There are advertisements in some communities, but I didn't pay much attention to them. Commercial activities usually attract patients in this field with free resources or services, find prospective customers, and then guide customers to buy. This is a marketing model.
As for what products and services are, it is not known. You can get to know them first, think calmly and rationally before making a decision. If my family has cardiovascular and cerebrovascular diseases, I can provide advice and help.