Today my freelancer engineer billed me 180 hours despite not having a deliverable prototype. I was shocked. I paid him. When does work ever get done on schedule or within budget? Rarely.
How much of the prototype is "I have an idea in mind but have never thought it through but know what I want it to look like" and how much is "written / drawn wireframes and explanations that have then been reviewed and planned with the two of us"?
I cannot feel too bad for what is over a months highly paid work that you did not have control over. If you did have control, why did it take 180 hours to kill it?