Possible scam ?

So this one is rather new to me but maybe someone came across and if not, I’m just trying to get a peace of mind…

I sold a card game, relatively cheap as it was one of them- either charity shop or I’m selling it for close to nothing, which was 1£.

I received a message from a seller saying that they will buy if, asking I can post it as soon as possible. I posted item following day.
Not long after I received a message from buyer saying that they are happy with parcel and that they left me a review, requested one in return. Not a problem, done.

After a week I receive a parcel to my house, to my surprise, it’s same card game! Received a positive feedback and a confirmation that buyer is happy with parcel.

I went back on Vinted to contact buyer but…. Member is blocked ?
He has 5 positive feedbacks, but I’m just so confused. Should I be worried?