It is very difficult to work out exactly what is going on, especially in a foreign system. The lawyer says the Trump people are trying every trick to stop this man and many others having a proper hearing. It looks like they are sending notices to attend court to get them to attend a hearing. Then they are asking the judge to dismiss the hearing so that they can arrest them and summarily deport them. In this case, it looks like the judge refused, so instead they used another route where they simply used their power to declare that the court hearing had been arranged by mistake.