An Internet Service Provider whom I used in the past, claims to provide me with Internet service. However, when I gave his technician the Hybrid Fiber - COX MAC ID on my Modem, he could not find it on his list. Also, the Internet Service Provider doesn't even have my current mailing address. All he has is my phone number and he is demanding payment. On the other hand, I use a cable service which provide TV. At this point, the Internet Service Provider is threatening to disconnect my Internet service.

My question: How can I verify if I am getting the service from him or through the cable?