As most responses in this thread indicate, talking to the vendor directly to let them know the issue would be the simplest way of dealing with any problems in regards to the product they are providing. In the original example given where there is an unusual amount of defects in the packaging, the best course of action would be to call the vendor, and ask them plainly what happened? Discuss what went wrong, and how it should be corrected. As a PM it is your responsibility to make sure everything goes smoothly throughout the duration of the project. If the vendor is reluctant to fix the problem either because they refuse to or possibly cannot, then it is time to consider weighing your options. You could do a risk assessment of the defective packaging; which would entail testing the packaging to see if it would still do what it needs too. If not then it is more than likely time to start looking for a new, more reliable, vendor. Someone who can make the proper packaging without any issues. This may cause for a delay in time, but its better to be accurate than to create a faulty product. All in all the fix for an issue with a vendor can be as simple as calling them. Mistakes are bound to happen, as humans it is what we do, and they are fixed most easily by being pointed out and corrected.