Where you are dealing with a returned TC664 from the customer check whether Article 59 applies.
When a claimant moves from one member state to live and/or work in another EU member state Article 59 of EC regulation 883/04 applies to ensure the smooth transition of the payment of family benefits (CTC and Child Benefit) from one member state to another.
Article 59 provides that where there has been a change in competency during a calendar month, the Member State which was paying family benefits at the start of the calendar month must continue to pay until the end of that month and the Member state in which the customer arrives will be competent from the start of the next month.