Amazon Seller Won’t Provide Return Label

I had bought a parts kit for an RC car on Amazon and waited nearly a month for it to arrive just to find out that none of the parts will mount to the car (the product name clearly stated it would fit my particular model) so I request a return which is approved but the seller is doing everything but send the label. They offered a 50% refund and told me I could keep it but since I can’t use it, there’s no point in keeping it. I told them I wanted a complete refund for it and a return label. They wait days between replies and I’ve already contacted Amazon who told me they must provide a label before the date closes in June but the seller won’t cooperate. Is there anything I can do to get my money back or am I just screwed?