Tmobile not honoring their promo

So back in Oct. 2023 I purchased 2 watches, the galaxy classic 47mm, on the promo of "get (x) amount of dollars off" (I can't remember the exact amount but it was a lot about $300, $350, or $380 off).  Tmobile was also running another promotion at the time called "bogo."  The main difference in these two plans was the 1st mentioned promo required a paired digits watch plan, and the two promos were also for different size watches & models.  I remember the sales rep questioning if I could get the 1st promo because something strange was in the fine print, the specific watch I purchased was listed in the fine print on both promos and he and I were discussing how that didn't make sense who would chose the "bogo promo" instead of the "x amount of $ off" you obviously save more money when buying 2 watches on the "x amt of $ off," he even went to ask his manager to verify and he agreed. Anyhow,  I made the purchase and he said he was making sure to write in the notes what promo he sold me on to make sure I get it and not the "bogo" well...fast forward when the bill finally stared showing the promo discount amount it stated "bogo" so I called to discuss the issue and the tmobile rep in the USA had all kinds of reasons that didn't make sense like: maybe you didn't have enough credit to finance the watch" or "the watch exceeded the the promo value" so I asked her to read the notes from the sales rep who I purchased the watches from to see he wrote down the promo code so she looked and said he didn't write anything and she even had a way to search the tmoblie archives of past promos and read them to me and it didn't say my watch on it which means that tmobile eventually caught the mistake and deleted all evidence of it in their system and in my order notes.  Funny thing is that promo is still going on today but it's written correctly now but they won't honor it for me because according to them it didn't ever exist like that back in Oct 2023 when made the purchase and she spoke with her manager and manager refused to get on the phone to speak with me said to tell me "we are not changing it and that's it so you have no need to speak with the manager" then I said we'll I can just call back and probably get another call center and speak to a manager then to escalate my grievance or go in person to a store then she finally agreed to put the manager on but conviently  "their on the other line with someone she'll call you back" but the manager never did. I've been a customer for over 10yrs but never really had a reason to speak with tmobile because I hadn't upgraded my devices in 8 yrs and as soon as they are paid off I dropping tmobile and telling everyone I know.  I'm still going to submit a grievance for dishonest sales practice and deleting/ falsifying records.