Select correct verbs.

If you had not contacted hotel reception during your stay last week, we would not have discounted tickets to the aquarium today.

If you had not contacted hotel reception during your stay last week, we would not have discounted tickets to the aquarium today.

This is a 3 type, negative conditional indicating a positive outcome (you did contact reception). Use if + past perfect (had contacted) to indicate an unreal condition in the past.

If you had not contacted hotel reception during your stay last week, we would not have discounted tickets to the aquarium today.

In 3rd type conditional, use would have + past participle in the main clause.