Refund held hostage

Terrible refund and return policies when purchasing with a gift card and credit card in one order.

I ordered 10 items and returned 3. The greater portion of this order was paid with my credit card, however when returning the items and selecting it to refunded to my credit card. The full gift card voucher was refunded. I flagged this and was told that’s how it work when using a gift card on Superbalist. The items I have kept 7 out of the 10 equate to a higher value than the gift card and would therefore be fully redeemed. I have been emailing Superbalist since the 18th of December to get this resolved and received a call today to inform me that this is just how their system works and nothing can be done. So I’m forced to purchase from them again?