First of all,to you and everyone else in this situation my advice is:
Ignore them. This is because they trying to put pressure on you, and if you respond it means they are starting to break you down. And if you respond then this means you are going to get into a dialogue with them which means they can put more pressure on you and you will end up paying their extortionate charges. But if you totally ignore them and blank them out they will not even have the reassurance that their messages are getting to you e.g. you may have changed your number or e-mail address or moved.
If you do the above is is highly unlikely that they will ever visit you at this is very expensive - and you do not have to let them in or even talk to them - so the visit would have been a waste.
It is also highly unlikely that they would take you to court as this is also expensive and in most cases does not get them their money. Another reason they will not take you to court is that no judge is going to entertain their extortion charges and bullying.
Basically - PLAY HARD.