Whose Fault is it?

Yesterday was Saturday, my rest day and the day Typhoon Rammasun landed in the city I'm living in.
The wind and rain were very heavy and very noisy. As a result, I didn't sleep well and I had another busy Saturday. The bad weather made many accidents happened. For example, one of our part-time teachers, L, said that she noticed she didn't feel well this morning and she couldn't go to the office. But, the students were there already and were waiting for the class to begin. However, there was no teacher in the office at that time.
" Tell the students that the lessons are cancelled because the teacher had a car accident on the way to the class," my boss ordered on the Weichat. Then she said to me," Amy, I know the real reason why the part-time teacher didn't come to the class. When you asked me how much the other part-time teacher got paid in front of W a few days ago, I had a feeling that something bad would happen. And now, it happened. Don't do that next time. W and L are good friends. W must have told L how much the other teacher was making, so she didn't go to class today. Remember, be cunning enough next time."
I felt very wronged. I had asked her the question about payment in a low voice at that time. Did W still hear what I said?
I went to the office to deal with something.
" Amy, don't ask L to go to the class next time. She's so irresponsible," W said to me.
" Why? " I was surprised. I thought she would intercede on L's behalf.
" This morning she called and said she didn't feel well, and didn't want to go to the class. She asked me to apologize to the students. Why? That's her own business. She's so irresponsible." W was really angry.
But I knew what happened. W didn't hear what I said at that time, and L didn't go to the office because she didn't feel well, not because of me.
I knew that it wasn't my fault. But, so what? Can I explain this to my boss? What can I do?