I don't know if something can be done, but I will report here my findings...
Already report to the moderators also.
Thank you, that's a good catch.
There is also an active thread for reporting a merit abuse, some DT members actually follow that thread. Technically, sale is also an abuse of merit system.
https://bitcointalk.org/index.php?topic=2896910.0Merit buying is just stupid, why would anyone risk his account at a cost of getting red trusted or even banned? I can see only one reason to risk your hard earned cash and precious (if Full Member and above) account. The seller should write you a cool article, which would be very useful for the community.

Then nobody will question your merits, assuming it is not a plagiarism (ouch). Oh, I just created a new job, a merit copywriter.
I support that. You can't buy an ability to write texts and produce valuable ideas. And It won't be a problem to catch and ban someone, who's merit will be in question due to some indecent behavior.