Review on Bandai Tamagotchi 4U White by Kevin Flores

We liked it when we first got it. However, about 4 months have passed and the screen no longer turns on. Never dropped or damaged. My stepdaughter played with him every weekend when she was with us. Since she is with her mother most of the time and doesn't take him with her. I don't know who to turn to for help. I want the company to help. Batteries work, there is sound, but the screen is black. Is there a guarantee?