I need advice

I bought these 6 knives off the swap all crkt snap lock or hole in one. And when i received them 3 of them had rust and one had a rolled edge big enough to catch my finger nail what would a fair refund amount, they all seem pretty used

I bought these 6 knives off the swap all crkt snap lock or hole in one. And when i received them 3 of them had rust and one had a rolled edge big enough to catch my finger nail what would a fair refund amount, they all seem pretty used