Can my botched granite repair be corrected?

Shortly after my kitchen was installed I noticed 3 scratches in the angolan black worktop. I have no idea how they were caused or when. The installer came back and said he could 'disguise' them. This he attempted by buffing in a black paste. I now have a scratch with a broad black outline that reflects the light differently from the rest of the worktop. It stands out like a sore thumb! He then skulked off without checking I was satisfied with the job. Please advise!