Frontier Communications holding my mother's money hostage. Downey California

My parents switched from Frontier to Spectrum. Frontier owed my parents $75.61. They put the money on a credit card with my father's name on it. My dad passed away. When my mom tried to use the card with the pin given to her, it gets declined. When I call the credit card company for her (she does'nt speak English that well), they say they need a probate letter and his death certificate before they can address the issue of the defective credit card. There was NO probate. My mom automatically got everything that was my dad's. They told me I need a lawyer to fight for my mom's money. So, essentially, they are holding my mother's money hostage.