Oxford Management Services

They have been calling 5 times a day, 1 early morning, 1 late at night. I finally answered it and they had me on hold "don't hang up" and finally I hung up. I could not call back out on my phone for approx. 3 minutes as it would not disconnect. Is there a law about that? Thing is...these are not my debts. They are my step daughter who uses a pay by minute cell phone and gets a new number every month! I called them back and said she's 30 years old and hasn't lived here in 15 years...