tell him that you don't do business that way. people can be odd and try to make their problems your problems. you just don't do business that way. i tell specifically what i want. i want to be paid every month at the beginning of the month (exception made to a few people - but rarely) for the entire month's lessons. if a lesson is missed - it can be made up - but not refunded (as i rely on the income when i teach). that making up the lesson is the students responsibility (to call and find out what time to come later in the week).