"Tried cancelling an appointment"

My daughter had an appointment which was no longer needed.

My husband phoned up but it was engaged, he left a message to cancel it. To make sure it was cancelled, I phoned up again but couldn't get through. Therefore, I followed the instruction to cancel the appointment using the online form.

Thinking it has been cancelled, we received a letter at the end of the week basically telling us off for not attending the appointment.

I phoned up the appointment line and got through this time, the lady on the phone told me that they have my request on the system but didn't state what it was for. Generally, the service of this hospital is very good. However, if they are not sure what my request was about, I wouldn't mind they phone me up to clarify things rather than wasting an appointment that someone else could have.