I am not sure about your partner but you have an action.  If this is a third party collector, you need to be aware this is a violation of the Fair Debt Collection Practices Act.  Contact the Federal Trade Commission and state attorney general and file a complaint immediately, Then, contact the collector in writing only (if you know the contact information), explain this person arrived at 10PM each night and indicate this is a violation of the Fair Debt Collection Practices Act. Tell them to cease and desist all collection activity and explain you have reported them to the agencies above.