Your account statement is incorrect

I believe there has been a slight mistake.

I have just received your [DOCUMENT, ex. your account summary for June]. Unfortunately, I am unable to reconcile your invoices to the $[AMOUNT] figure you state as my account balance. My records indicate as follows:

INVOICE/PAYMENT                AMOUNT
[LIST INVOICES AND PAYMENTS, ex.
#2352344                     250.00
Payment, Check #123, 5/1/98            -250.00
#2342564                     500.00
Payment, Check #123, 5/1/98            -200.00
Balance                     300.00]

I have taken the liberty of enclosing copies of the above invoices and checks. Please check your records to determine the source of the discrepancy and call me at XXX-XXXX once the difference has been reconciled.

Sincerely,