when a person has a debt that has been turned over to a collection agencey/law office can the law office threaten to sue the person that owes the debt

The Fair Debt Collection Practices Act (FDCPA) prohibits a debt collector from making threatening action that they do not intend to take or cannot legally take, and the FDCPA applies to law firms as well. While a law firm CAN file a lawsuit against you, and therefore it does not violate the FDCPA, the questions is whether they INTEND to file a lawsuit against you. If not, then it violates the FDCPA.