All modules are brand-new and are guaranteed for one year by Panasonic. Please save all your packaging material until you are sure that your module is working properly. If you receive a defective module and notify us within two weeks of receipt, we will send a replacement and arrange for the defective module to be picked up at no charge to you (USA only). We will not provide refunds on KX-TD500 modules. We don't provide tech support on KX-TD500 systems or modules.