Question: Tmobile associate bricked my trade in. How screwed am I?

I traded in my Samsung S21 for a Google Pixel 7 Plus. I was told I would receive an $800 credit for the S21. After transferring my data, I took the S21 back to the store to complete the trade in. I didn’t wipe it before going to the store because I wanted to be sure I didn’t miss any steps and complicate the trade. When it came time to wipe the phone it asked for my Samsung password. I tried to log in, only to get an “invalid password”. I reset the Samsung password and it still wasn’t being accepted. There was another person in the store having the exact problem. Another associate said “no problem, we just go into the back door menu and wipe it that way”. He did some combo of up/down volume and power and it attempted to reboot but came back to a blank screen. No buttons would work, it wouldn’t turn on the display when he plugged in a charger, there was no response to any of the tricks he was googling. The phone was basically new, it was my backup phone and rarely left the house. It was fully charged and working perfectly when I took it in.

The associate told me he would ask another associate after they closed and they would take care of it. I was skeptical but he wouldn’t let me take it back home because “it was already entered into the system”.

Is there anything I should do or am I just out of luck?