Corrected Counterspell

You attempt to interrupt a creature in the process of casting a spell. If the creature is casting a spell of 2nd level or lower, its spell fails. If it is casting a spell of 3rd level or higher, make an ability check using your spellcasting ability. The DC equals 10 + the spell's level. On a success, the creature's spell fails. If the creature's spell fails, it no effect, and the action, Bonus Action, or Reaction used to cast it is wasted. If that spell was cast with a spell slot, the slot isn’t expended.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the interrupted spell fails if its level is lower than the level of the spell slot you used.