Quartz Countertop Issue

[Gabriel Rocha]

Hello, I recently had quartz countertops installed in my kitchen and are showing long streak marks along the perimeter of the piece. We tried soap and water but it doesn't remove it. Could this be a mark left by the fabricators tools used to cut the piece (it was a prefab piece but I'm still certain cuts were made)? My contractor initially after install said we can have those buffed out but now he is saying it's a manufacturers error and have to pay a specialized trade to fix it. My contractor also claimed that he went to the manufacturer and all their pieces in the color we bought had these markings but refused to rectify the situation. Whether this is true or not is undetermined. Prior to pick up of the tops I specifically requested my contractor to thoroughly check for any flaws, clearly he didn't if he is now claiming that all pieces had markings and were evident at that time. Can I hold my contractor liable for any of this? Especially for taking a product that he is claiming had known issues at the time of pickup?