XG1v4 4K cable box

How do I get a XG1v4 cable box? We got a new 4k TV.  Comcast local store gave us a wireless cable box. However the TV sits in a corner where the internet connect is poor. So, we went back to comcast local store to request a coaxial connected cable box, the local store didn’t have Xg1v4. So, they said they will send us one. When the promised set top box came, it was still a wireless cable box. Please help us to get a coaxial connected cable box.