A problem throughout the reman industry.... Find a parts store who uses a good rebuilder and will stand behind the warranty. As far as returning parts not in the original box, many parts stores have that as policy....most times there rebuilder will not credit them for cores not in the original box.

As far as reman parts in general, you usually get what you pay for. The lowest price is not always the best part. I used to have a sign in the shop that said it best, "I won't argue with a man who sells his product for less, he obviously knows what it's worth".