I have a Panasonic cordless 2-line 6-phone system in my home. The handset for the base unit ceased to function properly; I purchased a replacement handset, KX-TGA939T, and I wish to register and use the this but I cannot locate our manual for the base set. The base set is Model {Panasonic KX-TG9381. I need to replace the manual . I do not find it listed on the Panasonic website. Thank you.