Then A Miracle Occurs... (Technology Servitor Attunement)
The Servitor with this attunement may, once a day, spend 1 Essence when performing a Song; this negates all Essence costs for the Song's use, even Essence used to increase the effects or the target number. The demon may still only use the equivalent of the Essence he currently has access to, however, and he may not use any actual Essence to power the Song. (So a demon with 5 Essence left could perform a Song and activate this attunement, spend 1 Essence, and then have 4 Essence-equivalents to power the Song.) This also means that the user of the attunement does not make the disturbance that spending the Essence normally would.
Note that "once a day" here means that the Servitor must wait at least 24 hours before using the attunement again.
I Think You Need To Be A Bit More Explicit Here In Step Two (Lightning Servitor Attunement)
This attunement allows the user to force another to make his point more clearly, in a manner of speaking. The angel may, when he sees or hears another person singing a Song, immediately spend as much Essence as he likes (up to his current maximum, of course); doing so activates this attunement and forces the singer to immediately spend the same amount of Essence if he wants to continue using the Song. This can only be used while the Song is being sung (it cannot interrupt the effects of a Song, only its performance); if the performer is successfully stopped, he loses any Essence already invested in the Song and is stunned for one round.
Disturbance from Essence spent to power this attunement or the Song occurs normally.