they said the 6 months of HBO will cancel automatically, I don't have to do anything.
It's real simple, just read what everyone else does. Ask for 'Customer Retention' specifically. Tell them you would like to get NFL Max and wondering what are the offers that are available, after the first offer, ask for a bit more and my guess is that you'll get a fair deal. I mean, you need to pay for something, so don't be greedy.