After Bing shut down, I started using AAdvantage Shopping to earn additional airline miles, but the company that is running that has recently denied several large purchases for no apparent reason. What other options are out there? Is there anything else that would let me accumulate airline miles?

I've gotten about $400 back using Fat Wallet. I like that you can get quick Paypal payouts. Plus it's a good place to find coupon codes.

http://www.fatwallet.com/cash-back-shopping/