Modern Edge Landscaping

Matt came to build a deck for me 18mths ago. it was nice in the first year. now 18 months later, i noticed at least 10 nails popping up in deck not under cover which is a trip hazard concern for me and my visitors!! i expressed my concerns via email and repeated phone messages but NO REPLY. I also wrote a note to his wife as she works at the same place but still have not heard from him... i am disappointed that he chose not to reply to me.does people not take responsibility for their workmanship??? also i learnt that maybe he should have used a twist lock screw type of nail rather than what he has used??? as i went to visit my friend house in point cook and it was a different type of "nail"