Hello from Amazon Selling Partner Support,
 
We understand that you contacted us regarding your shipment FBA18LKZB7P9 because the units are still not listed on your inventory despite being shown as delivered. 
 
After carefully reviewing the FNSKUs X003VWX2RD, X004GPKKEH, X004GPKKER, X004GPECOL, X004GPE31N, X004GPVGJP, X004GPNDO1, X004GPVNCZ and X004GPO2EV that are under this shipment. 

We are able to see that there are available units for these. However, the units included on your shipment are not the same quantities available for the FNSKUs due to following reasons: customer orders and other reserved inventory status( FC transfer and FC processing). 

For more information related to this topic, you may visit the help page below:

How Amazon receives and stores your inventory
https://sellercentral.amazon.com/help/hub/reference/G201081250