Hello Kangmin
To get the customer number or other info, please call the Contact Center at +41 848 44 66 88 (CHF 0.08/min.) or +41 51 225 78 00. For privacy reasons, I ask you not to post any info in the public community. If you have lost your SwissPass card, you can order a replacement for a fee of CHF 30. The SwissPass card is then valid for 5 years. If you still know your SwissPass login, you can also display the Electronic SwissPass on the SBB Mobile App and thus you will also see the customer number. You still have to show the SwissPass at controls on the train. However, I ask you to contact the number above for exact info.
Thank you for your understanding and have a nice day.
Kind regards, VlaznimA.