2.4 and 5.0 wifi bands question

I'm attempting to set up split bands for 2.4 and 5.0 ghz.  When I go through the prompts in the xfinity app and select "Save" nothing happens or I get a message that this cannot be done within in the app.  After a couple of rounds with the automated assistance I've given up.  Are there any human employees at Xfinity that could possibly help me?  Thank you