has anyone else been scammed by T-Mobile?

Same pattern here.  The only reason my wife changed her older iPhone with an iPhone 15 was due to a "special promo" that they would discount ~$350 for her phone. I haven't seen any indication of the promised promo and now their customer support says that there were no applicable special promos for her.  They said her phone's trade-in value was $5 but they actually gave her $25 credit (so I should be happy??). Look, she would not have traded her perfectly clean and functioning phone for $25 if they told me that at the store!!  I tried to fix this issue at their several TMOBILE stores and also via several support calls but no luck so far.  The senior management has reviewed the situation and there's nothing else they can do for us.  

Also, if you're trying out their 5G home internet service and return it to a store, be sure to call their customer support and have them cancel the line.  Otherwise, you'll be charged even when you return their device within the trial period.  Store employees won't tell you about the "right procedure" and it will be a hassle to fix the billing problem.  I ended up paying a payment overdue fee for the home internet service that I've never used. 

Lesson learned: I no longer trust any of their promos or trials. One more pain and I'll switch back to AT&T.  I'd be happy to pay a bit higher price than spending the time and energy to deal with this nonsense.  TMOBILE, to answer your question, I would definitely not recommend your service to my friends and family.