The reason why China Construction Bank's credit card statements can be found in QQ mailbox but not on mobile phones is that the mailbox is not bound through the mobile client.
Solution:
Log in to QQ mailbox through a computer browser;
Settings--Account--Enable pop3 or imap;
Bind.
The binding process is as follows:
1. Bring your own client---Settings---Add account;
2. Enter user name and password.
1. Set up the POP3/SMTP protocol, which means to collect mails and send them locally
POP3 receiving mail server: pop.qq.com
SMTP sending mail server :smtp.qq.com
2. Set up the IMAP/SMTP protocol, which means synchronizing server mail management
IMAP receiving mail server: imap.qq.com
SMTP sending mail server: smtp.qq.com
Both one and two can be bound, and the binding can be set according to needs.