Missing Receipt

I purchased an "out of stock" iPad (10th Gen) which had to be ordered by the sales person at the Apple store. The iPad arrived in 3 days and I went to pick it up. I was told several times that the receipt was forthcoming and would be presented to me after the exchange for my old iPad which was a "trade in." When the exchange occurred, I was told that the receipt was sent to me via e-mail. It is now over one week later, and no receipt has been received. Meanwhile, I have called Apple support three times, and have spent hours online searching for it with no success.