Wow, talk about a blast from the past. I haven't seen those since the late 90's. My cable co. began phasing out those things in 2000 in favor of digital boxes. I thought they were fascinating.
As others have said, I'm pretty sure it's not even listed on the account anymore. That thing is a relic. You could return it or you could keep it to show the kids later down the line.
I'm pretty sure the local office would have to make a call to corporate to figure out what to do with it first anyway, hahah.
My grandparents had one of these for the old UHF/VHF set in the early 90's or earlier: