Department of Education fails to pay my mother's gratuity

My mother worked for Department of education for more than 30 years, she passed away in 2019. She was a school principal at Tyutyu Primary School in King William's Town. Since her passing we never received her gratuity from the Department of Education. I went to the Department of Education at King William's Town to submit all the necessary documents in year 2020 but still to date no gratuity payment.