When using Defy on a spell that has been modified by Deflect (increasing its cost), does Defy still work, and does the opponent still pay the increased power cost?

Ruling: Defy can still target a spell even if its cost has been increased by Deflect, because effects that evaluate a card's costs always use the base cost. The opponent does not get refunded the increased power cost they paid, as power is paid when targeting and finalizing the spell, before Defy is played.

Sequence:

• Opponent targets a unit with Deflect (e.g., Qiyana), increasing the spell's cost
• Opponent pays the increased power cost and finalizes the spell
• Defy can still be played (checking the spell's base cost)
• Spell is countered but opponent does not get the power refunded

Nuances:

• Power costs are paid during targeting/finalization and are not refunded even if the spell is later countered