read your OG contract, and the one you just may have signed.... closely..that will tell you what you can and can't do.
saying an agent or rep said you could do something is not binding...
Actually what an employee of a corporation tells a customer is binding, unless something in the contract itself explicitly states to the contrary. And even so, if multiple employees give false information, and the customer relies on it, that can override this. This idea that the written contract is sacrosanct isn't true, but huge corporations get away with lots of things because no individual customer is going to sue them.
I skimmed through the post and honestly this doesn't surprise me at all, what does surprise me is the replies implying he got what was coming to him. Regardless of whether he posted a "wall of text", was "rambling" etc.. I believe he talked to 13 different people and got screwed, because I've had the same things occur to me.
When I've asked similar questions regarding changing plans in the past, I've asked for an email from the representative describing our conversation and confirming what the person told me (dont get off the phone before you receive it, if you do they probably won't send one, and you'll never get the same rep twice). Sometimes they outright refuse to, or give some junk about they can't send outgoing emails from their location. If you ask that their manager send one, they say its going to be a 4 hour wait til they can come by. On occasion the person is competent and will send one, mostly on small things that won't effect them much. I've even had hard copies of emails, taken that to a store rep and the person said "well, that representative misspoke, sorry we can't change your plan back."
At this point its pretty much their word (or whatever notes they wrote, if they wrote any) against his. Lesson from this is to keep trying to ask for a reply in writing describing the discussion if possible although even then sometimes it doesn't matter.