sold me a blunt scissor they wont refund.

hi i purchased an beard scissor on tuesday,28 may 2024 online.never saw product.online only.picked it up as a collect item.went home ,opened it and tried to cut a beard and it was blunt,phoned them now,30 may 2024, and the supervisor said because i opened it,i cant bring it back.i wonder how will you know if a scissor is blunt or not,if you dont open and try and cut with it,anyways they lost me as a customer forever.extremely bad service.