How can I get an xfinitywifi hotspot to resume broadcasting wifi on 2.4 GHz

For many months I've accessed a public xfinitywifi hotspot using my tablet which only supports 2.4 GHz wifi. About 3 weeks ago it stopped being able to connect to it. In fact it doesn't even show up on the list of available networks. Yesterday and today I checked it out again using my phone (which supports both 2.4 and 5 GHz wifi) and found that the hotspot was no longer broadcasting on 2.4 GHz. Only on 5 GHz. The phone connected to it just fine on 5 GHz. So it seems like the hotspot is still functional, but has stopped broadcasting on 2.4 GHz.  How can I get it to resume operation on that frequency?

As background, this hotspot is on a utility pole in a commercial/industrial park, and not associated with any of the nearby businesses (I checked with all 3 nearby businesses and all use Verizon as their ISP).  I used the signal strength of the 5 GHz wifi from the hotspot to pin down its position to the pole (the signal is -40 dB at the pole and between -55 and -60 dB near the adjacent buildings).

I have tried contacting Comcast technical support by phone, but can't get through the automated system as it does a check on my home internet and tells me that all is ok.  I got through to Comcast technical support chat from Facebook, and was told that all hotspots where associated with homes or businesses and that they couldn't do anything about how they worked (I think they were just blowing me off).

Any helpful suggestions on how I can contact someone in Comcast that can restore operation of this hotspot on 2.4 GHz?