I am writing to ask you to please make up the shortfall immediately and to ensure that such errors do not happen again.
Could I please ask you to look into these matters.
Please send us a corrected invoice for $9,479
I enclose a copy of the book with the errors highlighted. Please re-print the book and send it to us by next Friday.
Otherwise, we may have to look elsewhere for our supplies.
I'm afraid that if these conditions are not met, we may be forced to take legal action.
If the outstanding fees are not paid by Monday, 10 February 2014, you will incur a 10% late payment fee.
I look forward to receiving your explanation of these matters.
I look forward to receiving your payment.
I look forward to hearing from you shortly.