If you are European (Italian for example...) this link could help you: https://commission.europa.eu/live-work-travel-eu/consumer-rights-and-complaints/resolve-your-consumer-complaint/european-consumer-centres-network-ecc-net_en
-- Sweelinck

Consumer law does probably not apply to private sales!

Did you e.g. use some kind of marketplace platform that states that you agree with certain responsibilities of seller and buyer?
If not, and you didn't discuss what party took what risk, you knowinly took the risk and you're on your own now.