The postal express arrived without informing me, saying that mine was slow delivery without informing me. Is this normal?

Their statement is wrong. According to Article 37 of the Detailed Rules for the Implementation of the Postal Law of People's Republic of China (PRC), the mail of urban residents should be delivered to the mailbox or mailroom on the ground floor of a bungalow or building according to the address of the recipient. Mail that must be received and sent by postal enterprises or their branches with notices shall be collected by users. The parcel belongs to the mail that must be notified, so the post office must send the notice to your door or mailroom according to the regulations. If you don't deliver according to the state regulations, you can complain to the superior unit of the post office or the local consumer association.