misslady
I'd also like to add that most collection calls could be on auto-dialer. If they don't get an answer, it'll be set up to redial a couple hours later.
If they're calling for your daughter, simply tell them she's no longer at your address, but you can send a message to have her call them.
It can't be classified harassment, if they aren't talking to anybody. Collection companies can only call between the hours of 8am and 9pm, and depending on the state, no calling on Sundays.
If the calls continue after you explain to them that your daughter isn't at your address, then you can send out the cease and desist letter.
Regards-
Mike