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.
If you determine that this membership is not for you, you can always e-mail support@j-novel.club to inquire about a refund.