cancel now mobile pre activation

An xfinity agent talked me into switching to now mobile service a week ago. She said if I want to cancel my service in 14 days, I will get the full refund. I paid for the first month but I have not activated the service yet. After seeing xfinity support, realized it was a bad decision. For hours I am trying to cancel the service but xfinity couldn't make the process harder. All live agents and calls, just telling me I have to contact now support chat. NOW support chat is a useless bot, which is looping through pre defined subjects. All I got so far is from FAQ, navigate to NOW portal and find cancel pre-activation but there is no such an option in NOW portal. How can I cancel this service and get my money back? By the way, I didn't purchased any phone, just the service. I am thinking about disputing the charge from my card but I have home internet from xfinity NOW. knowing xfinity,  disputing the charge might somehow on my home internet bill. And to be clear, it was not a bundle, NOW home internet and NOW mobile service are separated.