Today, I received a short message saying that I became a member of E Long and sent me a membership card by ordinary mail. But I don't know why there is this card.

That's a promotion, or an advertisement. I have received such a phone call, and everyone knows my name. Hehe, they just want to let more people know about them. As for how they know your phone number or your address, hehe, I don't want to. Now is the internet age, it should not be difficult to know! ~ under normal circumstances, even if there is a membership card, housing or something will not be cheap! ~