I have had some experiance with Tenyfly as well, and can understand where WBusa is coming from. I have twice ordered parts from Tenafly, both times I got exactly what I was looking for, and both times the packaging was fine. One order was for a gasket kit, so you can understand that bending the headgasket just a bit and it's not useable.
Having said that, both order took longer than I would have liked, I too suspected that the items were not in stock, or shipping is very slow. One order I was billed for twice, but that was quickly fixed with a phone call.
I'd buy from them again, if it were a part I could wait for, but beware, the price is great, the service ... not so much.
One last thing I've learned, if it's a Cummins part you need, buy it from Cummins!Better price, better service.
Good luck