netmeg - 1:38 pm on Jul 13, 2013 (gmt 0)
If I were your client, I'd try to explain the whole situation (calmly and politely - it's an outlier, so don't get excited) in the Google AdSense Forum, and convince a top contributor there (Gracie is a good one) to flag an AdSense rep for some personal attention. It might not work, but then again, it might work. Costs nothing to try.
AdSense contextual never did a thing for me, although category banner ads and/or specific products do well. You might also try media.net, depending on your level of traffic; from what I understand they use Yahoo and Bing ads. They don't do much for me, but others have done better with them.