"send them back", I think the shipping cost back to China would probably be on the high side, even if I, as a private person, can find a company to take them.
Personally, I would argue that it's their fault and they shouldn't bother me when shipping faulty/non-new/wrong/etc products, so they just have to refund me. But I'm not sure if this is the result.
From my end, I'm pretty sure I did my best to get decent capacity tests.
@Will Prowse did post an update to that video, saying they're new cells and "
I used the barcode under the covers for verification. ", as said, mine have their QR codes scratched off.