Hi everyone,
This is a bit of a WWYD situation, so I'd be really grateful for any advice you might have please 
I work as a tutor, and have been teaching French to a girl for a couple of months now, but fairly infrequently (we manage to fit in around a session a month).
At the start of May, the girl's parents had provisionally arranged for her to have a tuition session with me this morning.
I travel to the family's house for the tuition, and when I got there I rang the doorbell a couple of times but got no answer. I waited for a few more minutes and realised their car wasn't in the drive, so I rang the house phone. I could hear it ringing but no one answered. I also tried a mobile number for the family, and again got no answer so I left a message on the landline and mobile.
The family got in touch a couple of hours ago to say they were really sorry but were out at the time of the lesson. They said they'd tried to send me a text earlier this week to cancel today's lesson but that they've only just realised that the text didn't send.
I have a 24 hour cancellation policy, so if my students cancel without 24 hours' notice or don't turn up to my lessons, I charge them for the lesson.
Considering the family tried to send me a text message to cancel the lesson today, WIBU to charge them for the lesson?