Memo reply - non submission of stock statement from our customer

Sir, I have received a memorandum from my higher authority for non submission of stock statement from our customer in cash credit account, i have done my follow up continously with the customer though the customer has failed to submit the stock statement, i have to reply to my higher authority for the memo, so please suggest me how to reply in the correct format and paras for the same so i can reply it earlier.
Thank you for cooperation.
With regards
vishal

Dear Vishal,
Though there was no gap in efforts, there appears to be gap in communication. Just because you did not receive stock statement from the customer, you cannot remain uncommunicative with your senior authorities. You could have intimated your follow-up to seniors through weekly/monthly statements or through separate mail. Since you have not communicated anything to your seniors, it is perceived by them that you did not do anything.
When your efforts did not yield results, you could have kept your manager informed. When manager also fails, situation merits escalation to still senior authorities.
Now coming to the solution. In your reply, write about your follow up. If you have written the mails then write about it also. If you had kept your seniors informed then write about it also. Write the reply in chronological sequence.
Thanks,
Dinesh Divekar