I'm trying to come up with a name for "the acceptance of a delivery." I'd like to be able to say
Ten deliveries were made but there are only five [fill_in_the_blank_here] on record.
Receipt works. As in, "receipt of the items has been acknowledged."
Likely variations for your case would include
"Ten deliveries were made but there are only five received items on record."
"Ten deliveries were made but the records show only five items were received."
Receptions could carry this meaning here,
and deliveries are often received at a reception desk, or simply at Receptions.
The word you are looking for is Received
Ten deliveries were made but according to our records only five were received