How long did it take you? How much do you need to charge for your hourly rate? Sounds like you may have priced it too low for the time spent there initially. That's your problem though. Working for neighbors can be sensitive. We did almost 8K worth of work for my neighbor right next to me. So far so good. I'd be an idiot to pass that work/money up. I will pick and choose the work I do for neighbors. Things like lawn treatments I tend to stay away from. Nobody has irrigation and when it gets dry, like it does every summer, and your control practices for weeds becomes useless, seems like you still should be producing a good lawn for them. I'll do landscape projects all day long if that's what they want.