I need some advise. I planted a lawn for a customer. After we finished his lawn I told him as I tell all my customers if he has any problems or questions about the lawn let me know and we will fix it. About 3 weeks later I see this guy and ask him how his lawn looks he said it looks excellent but he had two small spots that didnt come up so I went over the next day and patched the 2 spots he showed me the rest of the lawn and said he was happy with it, approx. 1 1/2 months later I was ridding by his house and see his lawn is covered with large brown spots but I didnt have time to stop and look at them so I gave him a call that evening and asked what happened to his lawn. He started spewing off about all the weeds that were in his new lawn so he called someone to spray it, he wasnt sure what they used but they put it on by hand and it killed everything including the grass. I would like to keep this guy happy but I dont know what I should do now. Any suggestions?