To the best of my understanding, skills expended for defense can't be Meditated back without Magic Items that specifically say you can, such as Recharge Prowess; most of the time, this will be skills like Parry or Evade, but in this particular case it happens to apply to a spell.
The main reason for this is that under normal circumstances you can only Meditate back a skill that missed, and the nature of defensive skills means they can never miss. Counterspell converts a spell into a defensive skill, and the rule of not being able to Meditate back a defensive skill now applies to the spell.