Formal email 

Good morning Miss Beltramini,
I am Chiara Aprea from 2^LSCA and I am writing you to ask what time the lesson on Monday  will start. I hope I will not disturb you but I was unable to contact my mates because a phone problem and I couldn't  consult the timetable.
I apologize for the inconvenience and I wish you a good evening.
Your sincerely.
Chiara Aprea