I did that a few times, thus the cursing and putting it away again out of frustration. As a matter of fact, when I looked closely the last time, it looked like a couple of the teeth were misaligned, and I'm afraid that was from trying it too much. I think I'll take it back in tonight for them to have a look at and see what they have to say. I'm a bit concerned that is isn't going to get better since I have tried to open and close it many times and it's remained problematic.
The only way I can get it to close smoothly is totally ridiculous - to sort of put my fingers under the zipper and slowly guide it along - but I actually peeled the skin off my finger trying that, so not a viable alternative!
What bugs me is that I work part time in a retail fashion store and we have some purses. I always check the zippers on our extremely inexpensive $30 PVC purses, and the zippers open and close so smoothly and we've never had one returned. The zippers are very lightweight and small, and sometimes I wonder if these heavy duty zippers that Coach uses are more of a nuisance than anything else.
If you haven't tried it yet this way.... hold one side of the zipper between your knees and pull the other end of the zipper with your hand to straighten out the zipper, nice and taut. With your free hand try opening and closing the zipper, fully and smoothly several times.
The key is to get the zipper straight and taut while you work it in. You may need to wax ( wax paper or clear/white candle wax) the teeth to lube them.
If this still doesn't work, you may indeed have a defective or damaged zipper.