Bait and Switch - Trade in SCAM

I had  the folks, including the head person, at a T-Mobile store offer to give me $1000 credit to trade in my 11 pro max for a new one. All I had to do was upgrade my plan to Magenta Max for seniors. I thought this too good to be true. I called 611 and asked if this plan was valid. A very nice lady with a interesting accent told me it was. She assured me I should allow her to sign me up over the phone. My monthly bill had been $80. I was surprised to get my next bill for $160. It seems that I was given only $400 for my trade-in. Numerous calls to 611 resulted in a lot of promises and a lot of apology but no action. I am now paying monthly until $1000 for the new device is collected. I really didn't need a new iPhone, it's just that I thought it was such a good deal. Yep! too good to be true. These people are experts at bait and switch. They have switched me out of a lot of bucks. No one so far is willing to fix it. 611 is useless. You are talking to folks out in the Philippines. Not sure they have the authority to do anything other than apologize.