Firstly, this is not affecting me or a 'friend' but does affect us all, from time to time, and a discussion today (that I'm not involved in - just reading posts) prompted me to open the discussion and wonder on the general consensus. So, the scenario is that you've purchased an add-on that the dev (or seller) has not stated that it comes as-in or without support/fixes. You install the add-on and you immediately get a bug that causes your add-on (or worse, the forum) not to work - either at all, or main/core functionality. For sure the complexity of the add-on and the complex nature of the bug impacts, so for the sake of this discussion lets say it's a medium level functionality add-on, and an apparent medium level bug. Where medium complexity equals something like extending user conversations and the bug causes that functionality not to work (throwing a 'blue screen of death' style error to the user whenever they click/activate this add-on).