Unfortunately, the expiration date listed is in error; it would be best to reference this topic instead when it comes to volume expiration:
https://forums.j-novel.club/topic/534/expiring-volumes
And please reference our FAQ for details on the differences between tiers of membership and how prepublication works.
https://j-novel.club/faq
If you determine that this membership is not for you, you can always e-mail support@j-novel.club to inquire about a refund.