Advice on a potential buy

I found someone selling something I’ve wanted for a while, it’s from an expensive brand, if I wanted to buy it new it would probably be around £300. They are selling it for way less. Potentially too good to be true. They aren’t advertising it as the brand but it seems all good. I’ve messaged them saying I’m interested and never heard of the brand and asked where they got it from. I’m wondering if there are people on vinted that sell stuff like this without knowing what they are selling or if it is probably too good to be true