I haven't paid and I won't, if you ignore it as I am, then, if they want to peruse the matter they would have to get a court order to send in the bailiffs. I highly doubt they would attempt this, as shady companies, a, do t want to raise attention to their dubious practices and b) they wouldn't win anyway, as I've never even used this services what evidence could they present? It's worth noting that such threating letters could easily be deemed as harassment and you have every right to contact the police and press criminal charges!