How to cancel Hbomax subscription?

I accidentally let my hbomax subscription expire, and when it wouldn't let me use the app without picking a tv provider I thought it was just a survey of who your tv provider is or they were insisting to know? Very confused I deleted the hbomax app and reinstalled it, but since there weren't any other options on the screen to proceed I selected cox (my tv provider) not knowing I was signing up for an hbomax account. It did not inform me of this at all, I thought I already had a working account. Now days later I find a hbomax account email in my spam saying to update the card on file or it will be canceled... So I guess hbomax canceled my account? Without letting me know officially... and then when I made the mistake of signing in with my provider (info autofilled) It billed a new subscriber without letting me know... I contacted hbomax and I can't figure out how to cancel/cancel auto renew hbomax from them, they said it has to be from cox... I spoke with support specialists at hbomax and they said I can only cancel the subscription/auto renew through cox... How can I cancel on that service/auto renew online? I do not see any options for it?  I want to delete my whole hbomax account and sign up again with my card as payment and not my tv provider? :( Please help