What are Customer Service Hours?

What hours is your customer service open? I called this evening, spoke to an AI bot who couldn’t help me with my issue (completely non working internet) and said a customer service rep would call me back in 10 minutes. That was an hour and a half ago and still no call. 
I WFH and had to upgrade to a mobile hot spot with Verizon ($10 more a month) because the service I pay Xfinity for won’t work and I can’t get anyone to help me fix it and I need the internet to work.