Patent infringement is the unauthorized use, manufacture, or sale of a patented invention without permission of the patent holder. If you suspect that someone is infringing your patent, you can take the following steps to stop them. First, gather evidence. That means collect all relevant information and evidence that proves the infringement. This includes any documentation, correspondence, or other materials that demonstrate the infringing activity. Next, send a cease and desist letter. A cease and desist letter is a formal notice that demands the infringer to stop their infringing activity immediately. It should include a detailed description of the infringement, evidence of the infringement, and a request for compensation. It should not threaten litigation, which would allow the infringer to sue you first. Finally, you can file a lawsuit. If the infringer does not respond to your cease and desist letter or refuses to stop their infringing activity, you can file a lawsuit against them. Patent infringement is a serious offense that can result in significant financial damages. By taking these steps, you can protect your intellectual property rights and prevent others from profiting from your invention. If you have more questions, I suggest consulting with an experienced intellectual property attorney.