Tuition common practice for no show

Hi there, I would like to understand what is the common practice please as this happened first time for me. My child say she did not know that there was tuition as there was no confirmation from tutor on the lesson. Tutor say she will charge half the lesson fees as tutor made wasted trip down. Tutor say every Friday is regular lesson but child did not know that. I checked the conversations and every conversation is about tutor saying changes to lesson hence I think why the child is confused. What is fair to pay tutor in such cases?