Constant, 2-3x daily calls from this number, automated messages in Spanish. When I call back number is "non-working number." How do I make it stop?!

I keep receiving calls from this number multiple times a week. The message is automated and apparently from a school advising me that my chihld has been absent from school multiple times and that i need to contact the school immediately using the same number given. My children have all been out of school and college for mor than 15 years (my youngest). When I call back to tell them to stop calling, it goes to a disconnected message.