Suddenlink demands I pay them for my own modem. Lubbock Texas

Suddenlink has billed me $70 for not returning my own modem, the same modem they sold me 2 years earlier.

I bought the modem from them in 2016 when they first became my internet service provider in Sedona, Arizona. I moved and canceled service with them 3 months ago. Last month they charged me for not returning my equipment, even though I do not have any of their equipment to return.

Suddenlink's customer service has wasted hours of my time, yet has not corrected their error. I have the invoice and canceled check proving I purchased my modem and the later invoices showing I never rented any equipment from them. Yet Suddenlink won't eliminate the charge, even though I have spoken to several Suddenlink reps who have agreed that their records confirm I never had any of their equipment and the charge is bogus.

Suddenlink's customer service seems to be set up specifically to make things as difficult as possible for its customers. After an hour long conversation with Suddenlink's online chat customer service, I was dismissed with the information that online chat couldn't help me, even though I had clearly explained my problem at the very beginning. Their phone support is no better, with long hold times to reach agents unable to correct even this simple case of negligent bookkeeping on Suddenlink's part.

Suddenlink is making the absurd demand that I pay them to keep my own modem, and they are threatening to send my account to collections if I do not.