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. We've created a template you can customize to request the return of your security deposit from your landlord. Refund checks will be mailed to the depositor or assignee within 10 days after the bond has been discharged, all applicable fees have been deducted. Security Deposit Demand Letter – For a tenant requesting to get back their security deposit. Sample. Download: PDF, MS Word, ODT.