Typically, a Demand Letter sets a deadline for the recipient to reply. If the deadline passes and the recipient ignores or refuses to agree to the terms in your Demand Letter, your next course of action is to file a lawsuit.  If you need to go to court to resolve the issue, be sure to gather evidence to support your argument (including a copy of your Demand Letter).  You may also want to talk to a lawyer, depending on the size of your claim. For example, if you’re suing someone for less than $10,000, you can typically represent yourself in small claims court. Keep in mind that rules for small claims courts vary by state.