Want to replace new cable box with XG1V4

I recently ordered a new cable box for my 4k tv over the phone. I asked for a 4K UHD compatible box with RF cable connector. I was sent a wireless cable box. I took this box to the local xfinity store and was given another box with an RF connector. However, this box is a PXD01 and is not 4K compatible. I would like to replace this box with an XG1V4 box. Can you help me do this?