Here's everything you need to know about not returning security deposits, including a security deposit refund letter template. Here are some tips on how to write a great security deposit return letter, plus a free template you can download and customize for your own use.Learn the basics of how to write a security deposit letter to a tenant. Sample Demand Letter for Return of Security Deposit. What to include in a demand letter when your landlord hasn't returned your security deposit. Re: Return of security deposit. The landlord hasn't returned my security deposit? To request a tax refund, file an Application for Refund - Sales and Use Tax (Form DR-26S) or Application for Refund - All Other Taxes (Form DR-26). To write a deposit letter, start with a formal greeting and state your request for the return of your deposit. 83.49(3), Florida Statutes.