IRS does not show receipt of an estimated tax payment, what do I do?

[baford41]

I entered an estimated tax payment of $1807 in line 65. I received a letter from the IRS saying they adjusted this figure to what they received, so I owe them $392.96.  They only show receipt of 2 payments of $448 each.  They do not show my first payment of $911.14.  How do I fix this?

[Lisa995]

Provide them a copy of the bank statement or canceled check to prove the payment was made and received by them.

[fanfare · Accepted solution]

"How do I fix this?"

furnish documentation (bank statement, cancelled check) for the payments that IRS misplaced.

The payments may not have been credited to year 2015.