[calewis]

Firstly, there are bugs. In everything, all the time. It's definitely not valid reason to not pay someone. Secondly, it's YOUR responsibility as the client to make sure what's being delivered is what you asked for.

Developers are not mind readers, you need to put yourself in a position where you are regularly reviewing progress, you don't need to be a developer to do this, just sit down with him/her each week and ask them to show you how the functionality works for the user. Sounds like a case of poor product management to me.