Well, I'm still not happy. Over a week after I submitted my problem, I just got a response saying that according to their records the check cleared the bank, and that I need to have the bank check the routing numbers.
So I called my bank. They say that the bank that issued the check returned as a duplicate presentment. However they are reversing the fee. Yay. But now I have to go back to the rebate company and hound them. Not sure this was worth $11.99.
On the plus side, my Home Depot rebate check arrived. Let's hope this one clears with no problems.