Explain the nature of the problem and verify that the product is still under warranty by referencing the warranty itself and date of purchase. Ask for verification on how and when the service or repair will take place.
1234, Main Street
Boston, MA 02123
<Recipient Address Goes Here>
I purchased <type of product> from your company on <date of purchase>. <Nature of problem>.
As this product is still under warranty <optional warranty number>, I <preferred action>.
I would appreciate you notifying me as to how we may resolve this matter. I look forward to hearing from you.
encl: <List of enclosed items goes here>