I had a new gas boiler installed last Dec at a cost of 3500. I have had a small leak from it since August. Have called and text the installer several times since then but he hasn't turned up to look at it. I know it's a busy time of year but I am disappointed at the fact that he has not bothered to take a look at it. Have used him for previous issues in my parents homes without issue. Any suggestions as to how to proceed ?