What else should I do about this mold I saw in a school?

Recently I was subbing at the elementary school. My mom is a teacher there and we were painting together. While I was there I noticed several areas with mold. I told my mom and she said she would tell the head custodian. He wasn’t there that day. That was months ago. I asked my mom if they did anything about the mold and she was like “what mold were?”. I decided to just call the principal and tell her where I saw the mold. And I reccomended she had the building inspected. I did that about a week ago but just remembered i saw mold elsewhere, so I called again but got her answering machine. I left a message and said where I saw the mold and hung up. I forgot to leave my number so she can’t call me back and there isn’t really a way of knowing whether she got my message or not. Should I call back and make sure she got my message?