Sometimes you have to get a reply to your letters by asking for it. This is inevitable in business, and it shouldn't be a major waste of your time. A standard follow up letter can do the work for you.
With a follow up letter you can also inform the recipient that you've asked before and won't ask again, depending on your decision in that regard.
It's usual to enclose or attach a copy of prior correspondence with a follow up letter, to clarify the subject matter, and in case it wasn't received.
Follow up letters must:Refer to the previous letter
State the subject matter clearly
Indicate if you intend to pursue the matter further
The example below indicates that the writer has decided not to take any further action if no reply is received.
Re: Previous correspondence (description)
I refer to our letter of 12th June 2010 regarding the above matter, a copy of which is attached.
No response to this letter has yet been received.
Please be advised that if no response to this letter is received by 12th August 2010 no further action will be taken in this matter.