The legal issue is part of the asymmetrical torture of the Tax Code.  If you made a payment of more than $75 and received substantial goods or services in return, the charity is obligated by law to give you a receipt that tells you how much of the payment is deductible.  That’s called the “quid pro quo” rule, and you can deduct only the excess of the payment over the value of the goods or services received in return.  (See Ready Reference Page:  “Charities Must Set Value on ‘Quid Pro Quo’ Gifts”) If your gift was $250 or more and you did not receive any goods or services in return, you are required to have an acknowledgment to that effect before you file your tax return if you are claiming a charitable contribution deduction.  The charity has no legal obligation to give it to you but you have the obligation to have it when you claim your deduction and most charities make it a practice to acknowledge all gifts.

In your case, if you are unsuccessful with staff, go to the head of the Board -- and consider whether there isn’t another food bank that would be more appreciative of your gifts.