I bought an apple wacth series 7 but when activated it didn't show apple so I charged it and the apple screen appeared and then the product didn't turn on anymore and the warranty was denied through a 3rd store.

Hello everyone, I bought an apple watch series 7 and activated it half a month ago, but when I activated it, the product didn't turn on and I charged it and the product showed Apple and still didn't turn on, so I sent it back to the store. I bought the product but when they sent it back to Apple, they said it was because I charged it myself so the product was damaged and the warranty was denied. I'm currently in Taiwan.