Legally, what is the appropriate amount of communication between a child and the non-custodial parent?

My husband and I have an issue with our daughter's mother continually calling and texting our daughter during her time at our house. We don't want to stop communication between them, but how much is too much? Our daughter mentions to us that her mother is asking questions about our personal lives, not just contacting her daughter to ask how her day went. This excessive communication is disruptive to our household, as it angers my husband and I that the mother is using her daughter as a pawn to get the information she wants, and it makes our daughter feel used. Could this be considered a form of harrment? Anyone else have this issue, and if so, how was it resolved?