The letter should state whether the deposit is being returned in full, partially returned, or not returned at all. Here's everything you need to know about not returning security deposits, including a security deposit refund letter template.Learn the basics of how to write a security deposit letter to a tenant. Re: Return of security deposit. If the building is sold, the landlord must transfer all security deposits to the new owner within five days, or return the security deposits to the tenants. You are now over a week late returning my deposit. How do you write a letter asking for a security deposit? In this article, we will discuss what to include in your demand letter to a contractor, what to avoid, and provide a sample demand letter. Once you have sent a refund request letter, keep it in your records. Reason for Refund: Clearly explain why you are requesting a refund.