Had an old debt I never honoured, but still under law it became invalid and extinct. Yet it gets resold and some specialist companies try to get anything from you, under 'amicable' terms.

They were harassing me, calling etc, and I wondered how they got my details after so long. Made requests for data they held on me, and complained to CNIL about their practices. They dropped everything and are now being investigated by CNIL on how they handle GDPR.