Restocking fee for defective iPhone 14

I upgraded both of my kids phones and my own phone 15 days ago. The kids phones are working perfectly. Mine is not. I been trying to exchange my iPhone 14 for a new iPhone 14 for the past 5 days. I have felt like a ping pong ball- T-mobile sends me to Apple, Apple sends me to T-mobile, over and over again. Yesterday was day 14 of having my defective iPhone, so I decided to go in store where I purchased it to do an even exchange since I was within the 14-15 day period after getting the iPhone. The rep in the store said that if I was Going to return it to T-mobile, I would have to pay a restocking fee of $70! I asked to speak to the manager. She said it was his day off but she would try to reach him. When she got him on the phone, she walked into the back to continue the conversation- out of earshot from me. She came back and said that he confirmed the $70 restocking fee. So I asked to speak to him. I explained that Apple sent me 2 emails stating that a customer should return a defective iPhone to the store they purchased it from within the first 15 days. The manager reiterated that they "have to" charge me the restocking fee. I asked what that money goes towards because they cannot put my defective phone back in to their inventory.. he couldn't answer that question. Called Apple when I left - I could feel the tears of frustration starting so I left and went out to my car. I was out there for almost THREE HOURS, being passed back and forth to T-Mobile and then Apple.

I finally spoke with someone from T-mobile who was able and willing to go above and beyond and actually sent me $100 from T-mobile but said it may not hit my account until today (it's in my account now), so I'm about to go back down to t-mobile to give them the $70 restocking fee from T-mobile directly.. he even added $30 for my inconvenience! So grateful! I am a little concerned because yesterday was day 14 of having this defective device… I am going to lose it if they tell me yesterday was the last day I could return it.