The WORST admin every!

The WORST admin ever! After FIVE years they charge us [house owners] for a rental to the Italian Embassy, who made application for the ADT service, paid up AND cancelled their membership. We only now receive letters from their debt agency that we are in arrears! Note, FIVE years later we get numerous letter to demand payment. The Embassy had numerous admin problems with ADT with each month's statement they received. By the way, 'our' account is now older than 3 years and therefore does not even require a response!