Unfortunately, probably not. The TH interface has always had "coming soon" or something on display in the top center for promotional deals coming the next day, and i think sometimes more than that. So if you purchased keys only hours before the daily reset that started the promo, i believe that would put you at fault for not noticing the "coming soon" that would have been there.
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Daddy Fowlersaid: Why is the treasure hunter promotion not available to me? If you buy keys regularly/recently bought keys, the marketing team at Jagex can see that and not give you the offer (since you're already giving them your money). So if you want an offer for extra keys, stop buying keys is essentially the way to do it.
"Volat Accipiter libera est; venandi sua natura est."