My position would be to fix the bugs as swiftly as you're able to deliver a product you're proud of, even if the core of it was not yours. Rather than totally

My position would be to fix the bugs as swiftly as you're able to deliver a product you're proud of, even if the core of it was not yours. Rather than totally sabotage the situation, suggest testing. Bugs found in testing allow the company to make informed choices while you and your CS department have an opportunity save the relationship by fixing the issues in development level software. (After all, we are all humans and bugs happen, even if the best of code.) There is a world of difference between development software and production ready software. Demo software is rarely the finished product. Now, if it was presented as 100% complete, tested and ready for production... that is a different story.