Here is very simple letter format for mailing Account balance to customer as well as asking him to provide confirmation for the same.
(Name of Party)
Sub: Balance confirmation as on 31st August 2013 as required by internal audit department.
With reference to the above subject, our books of account show a credit/debit balance in your account of Rs 10,000/- (Rupees Ten thousand only) as on 31st August 2013.
Please sign the confirmation slip below and forward this to us in the enclosed postage pre-paid envelope.
In case you need any further assistance including statement of account to reconcile the differences if any please do write to us.
We would be grateful if you would give this request your earliest attention.
If we do not receive your confirmation within 15 days, we would treat the above balance is correct.
For XYZ Limited
(Do not perforate the form at this point)
We confirm the balance as mention above as per our books of accounts as on 31-8-2013.
Date: Signature with Rubber Stamp:
Place: Name of Authorised Person: