This letter complains to a company about its staff being unable to answer your questions.
1234, Main Street
Boston, MA 02123
<Recipient Address Goes Here>
<time you interacted with business> I tried to <attempted business> I was very irritated to find no one able to answer my questions, and I thought I should bring the situation to your attention.
Did you know that you have employees who <problem with employees>? I'd like to keep doing business with you, but I hope you'll correct this problem before I try to do so again. Thanks for your time.
encl: <List of enclosed items goes here>