Donation + shadowmourne + discount code

Hello,

I received a 30% discount code during the New Year event. I donated 45 EUR specifically to buy Shadowmourne with the discount (150 → 105 coins). The code is valid, but the store says it cannot be used on this item.

This restriction was not mentioned anywhere before donating, and I would not have donated if I knew the code does not apply to Shadowmourne.

Please assist me by either:
1. Allowing the discount to apply to Shadowmourne, or
2. Refunding the donation so I can decide properly.

Thank you.