Nomorobo requires a simultaneous ring feature which isn't available for residential telephone service. Cox does not currently offer simultaneous ring as it is required for Nomorobo to function. We do offer some great alternatives to help you block unwanted calls. I would be glad to go over them with you. If I may, please send me an email to firstname.lastname@example.org with the service address and your full name.
Be sure to periodically check your bill statement under the "News from Cox" category to view any upcoming changes.