A campaign that generated 8,500 emails to the FCC opposing the proposed merger between XM and Sirius Satellite Radio has come under scrutiny, reports MediaBuyerPlanner.

According to the Washington Post, which checked 60 people whose names were attached to anti-merger emails instigated by the National Association of Broadcasters, most could not be reached. The phone either went unanswered or there were recordings saying the phones had been disconnected. Of the 10 people the paper was able to reach, nine said they never sent anything to the FCC.

The NAB bought pop-up ads on CarMax.com, Staples.com and PriceGrabber.com in August and September. NAB spokesman Dennis Wharton said that his group has the name, date, postal address and IP address of the emailers as proof that the letters were sent by real people.

Kelly Sullivan, spokeswoman for XM and Sirius, said the companies are suspicious: “The timing and pattern of delivery of these comments is highly unusual and suspicious. The letters lack any apparent common tie or indication of the source of the effort, all of which calls into question the legitimacy of the filings.”

The FCC declined to comment.

The TechDirt blog points out that the National Association of Broadcasters’ active involvement in the campaign against the merger weakens its own argument: “After all, if XM and Sirius really would represent a monopoly, then doesn’t that mean that the terrestrial broadcasters the NAB represents don’t compete with XM and Sirius and therefore shouldn’t care about the merger? Yet, the NAB keeps on fighting despite this rather obvious problem with its position.

Meanwhile, consumer groups have renewed their attack on the proposed merger. The Consumer Federation of America, the Consumers Union and Free Press argued in a report filed with the FCC that the merger would eliminate competition and hurt American consumers, writes Adweek.