one device won't connect

I made the mistake of reducing the speed to 300 Mbps and immediately lost my Ring Spotlight Cam's ability to show a live view.  Then I increased the speed to 1000 Mbps but still having the same issue.  The wifi is all of a sudden weak on the Spotlight  Cam when it worked great before the other day.  It's IMPOSSIBLE to reach a live person to speak to. There is no option on the Xfinity Assistant for just one device not connecting.   Please help!