Notice of unreturned equipment

I am a first time COX user. I had a router and 2 cable boxes installed on May 23rd. I keep getting notifications that I need to return my router or I will be charge. The router number in question doesn’t even match the one that was installed in my home. I have not been able to get a live person to help me with this issue. The one person I did talk to said they couldn’t see what I was referring to in my account and couldn’t help me. Can someone please tell me how I can stop the notification and remove the message that I have unreturned equipment from my account?