Kids syncup won't turn on

My sons watch as well won't turn on and because he has a scratch on the screen the store will not honor the warranty. I called T-Mobile and they sent a new watch over to the store when I went to pick it up the store will not give me the watch because of the scratch on the screen. This is nonsense. As a T-Mobile member for over 14 years this is unacceptable. They told me to add another line and get a new watch from the promotion and then after 3 months cancel the one I have. Which would be fine however if I cancel the watch I will have to pay it off in full. What's the point ! I am out a watch and paying for service I can't use. Disappointed at T mobile and how they treat their costumers. There is a software issue with the watch and T-Mobile won't take it back because of a scratch. Meanwhile when I bought the watch I thought I purchased the insurance but the agent never added it. Somehow that's my fault too.