I think the mention parts website is just an online catalogue store, they don't actually stock the parts and have anything in inventory, rather, all the suppliers just put their stock on the website, and when someone orders, the related supplier will just ship out the parts, under the Website store name, to the customer. The person order the parts would not know the difference.
On the returns, the process will take a lot longer, now there are two companies involved, and two re-payments.
So be patient, the money will eventually returned. TigerDirect operates in this manner.