debt collection

My daughter has been divorced for eight years, they have a 14 year old daughter. She had to have an ultra sound done in 2006. After insurace paid off, her husband received a bill for $750.00. My daughter received a call from a collection agency saying she owed a bill for this amount and with court costs she owed $840.00. According to their divorce settlement they are to split the cost half and half.
When her ex-husband's wife received the bill, she called the collection agency and told them it needed to be sent to my daughter. She gave them her SSN, her address, telephone number,and other personal questions they asked.
My daughter then received a telephone call from the collection agency saying she needed to pay this bill as soon as possible or they would take her to court. My daughter is on disability and receives a check for this.
After they were divorced and he remarried, they were told in court that his new wife was not to interfere with anything concerning the minor child. Any questions or issues was to be between the mother and father of the minor child. Is my daughter responsible for all the bill and is there any legal issues we can make on her behalf because of the given information to this collection agency by the new wife and them accepting and changing everything for my daughter to pay this bill?

[randalljd]

See marital debts: http://www.worldlawdirect.com/article/1560