You might want to consult with a professional but it looks like the only thing you can do is rip it up and start over. I don't think that it looks bad and unless it it is pointed out to them, I don't think anyone else will notice either. I understand the frustration however when you pay good money for something and it is not done properly. Contact the person who installed and tell them about your issue. If they refuse the fix it or refund your money, write a review on Yelp and attached this picture. Do not write anything libelous however. If you cannot prove it is true, do not say it. Companies can now sue customers for mean reviews on Yelp.