Hello and welcome to the forum! Friends & Family is available on Nationwide Single Line plans with 900 Anytime minutes or more, as well as Nationwide Family SharePlans with 1400 Anytime minutes or more. Is the fourth line of yours under one of these plans as well? It may not be. Other than that I see no restriction that would prevent that fourth line from qualifying for friends and family unless there is some kind of pending account issue with that particular fourth line.