Can't upgrade my phone online - why?

First before I share my recent experience let me just suggest to everyone having issues using the tmobile app to just go sit in tmobiles parking lot or even hang out in the store and LUEGO use the app to do whatever you need to do. DONT bother talking to any employees though its a waste of time. Also if you need to check order status you will also need to sit in the parking lot or hang out in the store to do so because once you are off tmobile property the app goes back to not working properly.
 

I tried using the app and website both to upgrade my phone and then yesterday ended up going to the store to get it taken care of and I learned a few things during my 5 minute visit. I explained that their app and their website both gave a white screen when I tried to add the device I wanted to the cart and then explained that I was trying to avoid paying upgrade fees and also mentioned which phone I wanted. 2 different employees both confirmed the phone I wanted was back ordered until July. Then they 1 guy told me that it would also cost me about $250 but he could knock back some fees and get the price down to $150. By this point I was trying to access the app to show that I wouldnt have to pay anything aside from taxes if I was able to do it through the app and this is when I realized I was able to get past that one screen that always refused to load. I even mentioned that the app suddenly seemed to work probably because I was in the store and the guy continued to argue that even if I could now use the app the price would be the same because it has to do with my credit and that the price was personalized based on my account. I was furious at this point and told the guy to forget it and walked out. While in the parking lot I noticed I was still able to access the full app so I ordered my new phone through the app like I orginally wanted to and guess what? Only cost me about $50! I am absolutely furious that I was lied to by not 1 but 2 employees and that 1 of their employees tried to scam me to get more money out of me!