热心网友
I am afraid that I've got to let you down. My shedule is full up to Sunday.
热心网友
I'm afraid that i will have let you down,because i have an appointment on Sunday.
热心网友
i am sorry to say,in my shedule i have no time till this sunday
热心网友
I hope you will not be disappointed as I have been fully ocupied up to Sunday.