Compromised Computer Notification from Cox Communications

I received an email on 8-26-17 claiming to be from Cox Communications that indicated that "Cox has identified that one or more of the computers behind your cable modem are likely infected with the Zeus Trojan/bot, also known as Zbot. While this malicious software is not new, it still poses a great risk to your computer and files that reside on your hard drive." 1) I want to make sure that this email is legitimate. 2) What devices can be infected by this virus? We have 2 smartphones, one laptop, and one iPad connected to our modem. 3) When I try to download the Security Suite software, I get the following error message: "We were unable to activate your Cox Security Suite service at this time. Please wait and try again later or call your local Cox Technical Support line for further assistance." Any help is appreciated.