XFi Gateway install killed wired wall jacks

An upgrade to the XFi Gateway a while back replaced the modem and router connected to our panel in the basement with a unit that sits upstairs with minimal wired ports.  It's worked fine for WiFi with 3 pods added, but killed all the wired connections that run through our panel.  My son wants his wired connection back for gaming due to some WiFi limitations.  How can I restore wired service to our jacks without messing up our WiFi network?  I do not believe that relocating the Gateway to the panel in the basement is going to be a solution due to WiFi reception issues.  Can I repurpose an older WiFi router with configuration adjustments?  Do I need an additional modem?    I now have a bunch of cables hanging out of the panel in the basement that used to be plugged into the previous router.  I tried plugging them into a gigabit switch which I originally purchased to connect other devices directly to the upstairs gateway, but am not able to get online via the wired connections throughout the house.  Thanks for any guidance you can give!