Encl: <List of enclosed items goes here>
<time>, you <action taken by the rep>. I am writing to let you know that I am very disappointed and upset at your actions.
<Even though I did not support you in the last election/I supported you in the last election> <I have/and I have> been a supporter of the things you have done since that time. But I cannot put my support behind this.
I think public and I deserve an explanation for your actions. Please respond to this letter in a way that makes it clear that public opinion matters to you. Otherwise, I will almost certainly support a different candidate during the next election.
Thank you very for your time and consideration. Would be looking forward to your response at the earliest.
Dear <Recipient’s Name>,
<Mention Recipient’s Address Here>