Upgrading phone poor customer service

So I called on 12/27/22 to obtain more info on the upgrade program to change my phone out to the Galaxy S22 Ultra 512GB model.   I was told if I trade in my Galaxy note 8 it would be a $1000 bill credit, which I also verified online.  The rep I spoke with by the name of Vaine gave me all this information she told me how much it would be monthly, she also told me how much more my bill would increase and advised me I would have to change my old grandfathered plan to one of the new unlimited plan.  She was very helpful in giving me this info.  So I advised her that I would think about it and call back.  Well I called back the next day and spoke with a rep by the name of Aaron.  He advised me that no the Note 8 would be a $800 bill credit increasing my monthly charge which  is not what I was told.  He was unable to do anything about this so I spoke with his manager by the name of Rain (EDITED).  She advised me the same information.  Telling me that even though I saw this info online and was advised by the first rep Vaine it was all incorrect information.  The only thing they would be able to do is credit me the activation fee.  I told them I do not want that I want what I was originally told.  After going back and forth about 10 min she advised me there was nothing she could do and cannot stay on the phone arguing with me she wanted me to contact consumers@att.com.   I had asked her how does the online website and a rep both give the same incorrect information at the same time, and how does it change overnight?  I told her to keep the waving of the activation fee I want what I was originally told and what your website and showed me.  After 20 years of being with Att they are unable to give me a simply 200$ increase to the $1000 I was originally advised.  I would love to see ATT come back and keep good on their promise they told me over the phone and on there website for $1000.  If this is how they handle long time customers I advise everyone to buy your phones else where or just go to a different carrier all together.