Entered on Official Boletin - what happens next?

This year in this area a new rubbish tax was raised in this area to be paid to a private consortium.  We received first an explanatory leaflet and then a bill which we subsequently paid.  However, although several of our neighbours received the initial information, they did not get a bill and therefore made no payment.  Their names, along with several thousand others through the Consortium area, are now shown in the latest Oficial Boletin. From what little we have been told, once a debtor´s name is published, he has to take steps to put matters right or else the entity owed the money proceed to reclaim the debt , together with interest, from the debtors assets without further notification to the debtor.  Can anyone please say whether this is fact and, if possible, outline what steps our neighbours should take to protect themselves.  It is worth noting that the neighbours are all permanent dwellers in Spain and not spasmodic visitors who could have missed the letter.