The delivery hangar in citadels seems to lack the option to search for items in them, as well as remotely either trash them, contract them or move them to your normal hangar.
Situation: You get something delivered in a citadel 50 jumps away. You only get notified once about what items they are and you cannot search your delivery hangar items anymore after the fact. Also, the sender does not get any notification that he delivered any items (no history).
After the delivery was done, you cannot access these items in any way unless you dock at the citadel. It should be possible, similar to all other personal assets, to access them, contract or trash them remotely without having to go all over new eden because someone delivered something to you (e.g. contract to an alt to move)
Also, it’s possible that it was delivered to a toon without access, and for all intents and purposes, the item might then be lost.