DMC calling my home at 6AM

STOP calling me at 6AM!!! DMC is calling me at 6AM with regard to one of my staff members. The rest of the office world starts working at 8AM, yet DMC is calling me at 6AM to speak to a staff member who only starts at *AM. And they are calling me on my private landline at my home!!! Fed up to say the least... DMC, you are the proverbial pain in the ***!