Would you have work that wasn't done right re-done?

If you are not pleased with the work, by all means call them back! I own a flooring store and we give a 2 year warranty on all our work. Just because they accommodated you by working a weekend doesn't mean you should have to accept shoddy workmanship. Plus you probably paid additional labor to have it installed on a weekend. I agree with the one comment about threatening to sue, this normally doesn't work. But a well thought out letter sent to the main office usually gets some attention. I'd prefer my customer complain to me, if I didn't know there is a problem I can't fix it.