Just send a bill back...ie, how long will it take to fill in, i reckon 20 mins...so send them a invoice for 20 mins of your time..why not start using your corporate person and make some money from it.
20 mins = £100. this amount is for documentation time.
see what happens.
Or just fill it out in lower case and in red biro, and cross out any parts you do not wish to fill in.
Request for payment.
Name of Addressee
Reference: In this section you need to mention subject of the letter briefly and concisely.
Dear Ms./Mr. (addressee)/ To whomsoever it may concern
The first and introductory paragraph of the letter should tell the addressee why you are writing this letter. This will inform the reader that they have defaulted on their payment on the bill that was sent to them by your organization. Do mention the date on which you had sent the bill to the addressee earlier so that he or she is informed of the same. Also send a copy of the invoice with this letter so that the addressee does not have the excuse of not having the invoice and also is made aware of the overdue amount.
In the second paragraph, you need to mention details of by when your organization expects the addressee to make the payment. Mention both the amount to be paid and the date by which it needs to be paid. Also ensure that you make the addressee aware that in case the payment is not made, the addressee is liable to face legal action.
In the third paragraph, you need to assuage the fears of the addressee by saying that you believe that legal action would be completely unnecessary. Also ensure that you mention that in case the addressee has already made the payment, they should ignore this letter. Apologize for the letter in such a scenario. End the letter by giving your contact details in case the addressee needs to contact you for any kind of clarification.