As a former buy.com customer, I do not recommend this store.
First off, there is no real way to contact customer support directly, not even through e-mail.
Second, their Order Status pages are sometimes misleading. I cancelled an item for not arriving at the expected date. Instead, it changed to out for delivery, and the tracking number says it was delivered to a different location. After a series of mishaps, I finally received it months after they expected delivery date.
Personally, I had no serious problems with buy.com. Processing returns is quite easy, and they even allow you to print a UPS shipping label on their own expense. I only had one problem on getting accurate information on Order Status and actually getting my ordered items. But the reason I cancelled my account is the lack of customer support (no phone numbers, no e-mail address).
(I had to cancel my account by sending an e-mail to their Privacy Policy Support page.)