老貓 is right. Here is my personal experience

I had a deck repair job done by a contractor and I paid all.  By contract, there is one year warranty.  After one month, one piece of new panel was out of shape. I called the contractor and he took the phone and promised to come to fix it next week, of course he did not show up.  I called him about five and six times in next few weeks and all went to his voice mail and no response at all.  Finally, I left message and stated that I understand he is busy, but the panel is causing safety issue and if he is really busy, I will hire another contractor to fix it and send the invoice to him for reimbursement and this will  my last call.   The contractor called me back 3 minutes later and apologized and fixed it the same day.