Recently I have had good experiences with Wal-Mart CS. Small issues but they fixed them.
I also made a new order when the price dropped and then cancelled the first, but it was too late. I never got the shipping email but there is a tracking number on the website. I did the online chat with CS and they refunded the difference between the 2 orders.
I haven't had luck with emailing them, as after filling in the form I got an email that said I sent the email to an unmonitored email address!