Can't Turn Off Public WiFi Hotspot

I restricted my kids' online time using the Xfinity app. This worked well for about a year, then Xfinity was able to contact my kids and inform them that if they pay $10, they can access the public wifi hotspot that's broadcast by my Xfinity gateway (named "xfinitywifi"). Now, I can't get my kids offline. I called Xfinity's customer support 4 times yesterday to opt-out of participating in broadcasting their paid wifi service (which doesn't pay me anything). All 4 times, they assured me that they turned it off, but here I sit 24 hours later, and it is definitely still turned on. 

I found 2 methods for turning this off: The first can be done from the Xfinity app - but gives me an error every time. The second can be done from their website, but gives me a message that staes "hotspot settings are unavailable".

What can I do to turn this public wifi connection off? If I can't find a solution, I'll be forced to switch ISPs.