Secondly, merely providing a list of the contributions will probably not satisfy the IRS in this case. While there is no requirement (or reason) to provide a list of contributions with the original return, if the IRS follows up on a charitable contribution deduction, they want to see “contemporaneous documentation” of the contribution, which includes an acknowledgment from the charitable recipient showing the date, amount, a statement that the recipient is a 501(c)(3), and that you received no goods or services for the contribution.
Non-cash contributions, (stocks, cars, land, etc) over $500 should include an additional form and may require additional support.
This is Form 8283 for 2020:
https://www.irs.gov/pub/irs-pdf/f8283.pdf
These are the instructions:
https://www.irs.gov/pub/irs-pdf/i8283.pdf
From the instructions, “You must file one or more Forms 8283 if the amount of your deduction for each noncash contribution is more than $500. You must also file Form 8283 if you have a group of similar items for which a total deduction of over $500 is claimed”
Despite the typical IRS jargon; it is not really very complicated. From the description of the problem, the second page of form 8283 did not get included in the electronic filing and has been sent in separately twice now in paper form. The IRS is hopelessly behind in their paper communications and it is causing a lot of stress for filers who have received notices and then no acknowledgment when they do what is asked and in fact receiving more notices.