I didn't receive a written invitation from China Railway.

The solution to this situation is to re-email, consult the relevant situation and ask for help.

1. resend mail: Try to resend the email or SMS notification to ensure that the email or SMS has not been intercepted or misjudged as spam.

2. Consult relevant information and ask for help: If there are other ways to contact the recruitment department of China Tower, you can contact them by phone or email to consult relevant information and ask for help.