Sorry for the weird question, felt like someone in this community would know how to deal with this.
I bought 5 packs of Dragon Shield Dual sleeves on CardMarket. They arrived fast and all packs were perfectly sealed. When I open the packs, 3 of the packs are defective. There's a black stripe on the top/bottom of the sleeves, which effectively mark them. These sleeves simply cannot be used. The other 2 packs seem decent, albeit with small defects on the side of the sleeves. Not big enough for me to complain, I think. They all come from the same batch.
I feel bad asking the seller for a refund, I don't think they had a way of knowing the sleeves were defective. The packs were sealed and the batch number is only visible after you open the packs. But maybe they have some sort of way to get the money back from their distributor or something? I have contacted them to see how to go from here but no reply so far.
I saw that Dragon Shield also has a contact form for defects but they warn me that since I didn't buy the sleeves from their store there is a very low chance they'll actually do anything. I submitted the form anyway to let them know that this batch is likely defective.
Who should provide compensation for defective sleeves? The seller or dragon shield?
EDIT: seller replied refusing any compensation, Dragon Shield has not yet replied. Lesson learned: I'll order from Amazon next time instead of throwing money away.
EDIT2: today, July 8th, Dragon Shield replied and offered me a full refund as a voucher for a purchase on their website, free shipping included. They stated that the manufacturing process of the Dual Mattes line makes this problem hard to avoid, though it was particularly bad in my case. I recommend avoid the "Dual Matte" line altogether.
Cheers!
