Stefan Doyno trademarked the slogan three years ago as the name for his jewelry business, and said he was shocked to see that Obama, a Democrat from Illinois, use the name as part of his campaign, White Plains (N.Y.) Journal News reported Thursday.

Obama's campaign manager reportedly received a letter on Dec. 18 from Doyno's lawyers informing them that the slogan couldn't legally be sold on any campaign merchandise because of its patent.

Obama spokeswoman Jen Psaki told the Journal News that the logo hadn't been sold on campaign materials and invited the young business man to join their grass-roots team.

Doyno reportedly planned to vote in the presidential primaries on Feb. 5 and hasn't said whether the "Change Rocks" discord will affect his vote, the newspaper said.