When a company offers a "no questions asked" return policy, it is still a good idea to tell them why you are returning the merchandise. It helps them serve you better in the future.
1234, Main Street
Boston, MA 02123
<Recipient Address Goes Here>
I am returning <merchandise> for a refund, as stated in your full refund policy. You can <disposition>. <Optional return authorization number.>
I am returning this merchandise because <reason>. Thank you for your prompt attention.
encl: <List of enclosed items goes here>