I donate to several organizations. I do not always get information of package arrival. I worry about that so I go ahead and use the USPS pink slip for signature confirmation and insure the item too. I find that all organizations are busy. Their method may be to wait for all the donations to come in before sitting and writing a personal response letter/note...to all their donors. Or they may collect all the names and item types to place in an organization recognition list on their web site. It does take a great effort to manage all the information correctly. If you have confidence in the organization don't give up.