Write the exact price you want to sell your cards. You’ll be able to negotiate later on.
A sale is not an exchange nor an auction, the buyer has to be able to buy it at the price written in the subject.
Write the name of the card/s you’re looking for.
Write the name of the card/s you want to give in return.
It's been 1 day, I think he is allowed to enforce it again because it still isn't fixed.