It is really easy to get rid of them , you have block options , another option is to ask in for confirming 20 minutes before
![Wink](images/smilies/wink.gif)
and if they don't came , you also can call them in the middle of the night to make some home problems. so next time they will tink 10 times before making apoiments
![Smile](images/smilies/smile.gif)