Freefonix - Everyone was Polka Yodel Fighting

Children's animation about a teenage band that discover a magic note, much to the chagrin of the record company moguls. When the Polka Yodel craze sweeps into Los Bosmos, BB suspects that there is more to the Polka Meister and Yodeler than meets the eye. It turns out that she's right; this musical duo are actually master villains in disguise, and what's worse, they're actually CC and DD!