Terms and Conditions 2x30% Promo
The customer buys 2 products → gets -30% .
If you return 1 of the 2 (or more) products → the promo conditions are no longer valid.
Then the discount is recalculated and the refund is reduced by the lost portion of the discount.
Example
Item A = €50
Item B = €50
Total = €100
30% discount → pay €70
If you return an item:
You are no longer entitled to the discount → the full price of the other item returns to €50.
So he was only refunded €20 (because of the €50, €30 had been “covered” by the discount which now expires).